1 2 #if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) 3 #define __SQLITESESSION_H_ 1 4 5 /* 6 ** Make sure we can call this stuff from C++. 7 */ 8 #ifdef __cplusplus 9 extern "C" { 10 #endif 11 12 #include "sqlite3.h" 13 14 /* 15 ** CAPI3REF: Session Object Handle 16 */ 17 typedef struct sqlite3_session sqlite3_session; 18 19 /* 20 ** CAPI3REF: Changeset Iterator Handle 21 */ 22 typedef struct sqlite3_changeset_iter sqlite3_changeset_iter; 23 24 /* 25 ** CAPI3REF: Create A New Session Object 26 ** 27 ** Create a new session object attached to database handle db. If successful, 28 ** a pointer to the new object is written to *ppSession and SQLITE_OK is 29 ** returned. If an error occurs, *ppSession is set to NULL and an SQLite 30 ** error code (e.g. SQLITE_NOMEM) is returned. 31 ** 32 ** It is possible to create multiple session objects attached to a single 33 ** database handle. 34 ** 35 ** Session objects created using this function should be deleted using the 36 ** [sqlite3session_delete()] function before the database handle that they 37 ** are attached to is itself closed. If the database handle is closed before 38 ** the session object is deleted, then the results of calling any session 39 ** module function, including [sqlite3session_delete()] on the session object 40 ** are undefined. 41 ** 42 ** Because the session module uses the [sqlite3_preupdate_hook()] API, it 43 ** is not possible for an application to register a pre-update hook on a 44 ** database handle that has one or more session objects attached. Nor is 45 ** it possible to create a session object attached to a database handle for 46 ** which a pre-update hook is already defined. The results of attempting 47 ** either of these things are undefined. 48 ** 49 ** The session object will be used to create changesets for tables in 50 ** database zDb, where zDb is either "main", or "temp", or the name of an 51 ** attached database. It is not an error if database zDb is not attached 52 ** to the database when the session object is created. 53 */ 54 int sqlite3session_create( 55 sqlite3 *db, /* Database handle */ 56 const char *zDb, /* Name of db (e.g. "main") */ 57 sqlite3_session **ppSession /* OUT: New session object */ 58 ); 59 60 /* 61 ** CAPI3REF: Delete A Session Object 62 ** 63 ** Delete a session object previously allocated using 64 ** [sqlite3session_create()]. Once a session object has been deleted, the 65 ** results of attempting to use pSession with any other session module 66 ** function are undefined. 67 ** 68 ** Session objects must be deleted before the database handle to which they 69 ** are attached is closed. Refer to the documentation for 70 ** [sqlite3session_create()] for details. 71 */ 72 void sqlite3session_delete(sqlite3_session *pSession); 73 74 75 /* 76 ** CAPI3REF: Enable Or Disable A Session Object 77 ** 78 ** Enable or disable the recording of changes by a session object. When 79 ** enabled, a session object records changes made to the database. When 80 ** disabled - it does not. A newly created session object is enabled. 81 ** Refer to the documentation for [sqlite3session_changeset()] for further 82 ** details regarding how enabling and disabling a session object affects 83 ** the eventual changesets. 84 ** 85 ** Passing zero to this function disables the session. Passing a value 86 ** greater than zero enables it. Passing a value less than zero is a 87 ** no-op, and may be used to query the current state of the session. 88 ** 89 ** The return value indicates the final state of the session object: 0 if 90 ** the session is disabled, or 1 if it is enabled. 91 */ 92 int sqlite3session_enable(sqlite3_session *pSession, int bEnable); 93 94 /* 95 ** CAPI3REF: Set Or Clear the Indirect Change Flag 96 ** 97 ** Each change recorded by a session object is marked as either direct or 98 ** indirect. A change is marked as indirect if either: 99 ** 100 ** <ul> 101 ** <li> The session object "indirect" flag is set when the change is 102 ** made, or 103 ** <li> The change is made by an SQL trigger or foreign key action 104 ** instead of directly as a result of a users SQL statement. 105 ** </ul> 106 ** 107 ** If a single row is affected by more than one operation within a session, 108 ** then the change is considered indirect if all operations meet the criteria 109 ** for an indirect change above, or direct otherwise. 110 ** 111 ** This function is used to set, clear or query the session object indirect 112 ** flag. If the second argument passed to this function is zero, then the 113 ** indirect flag is cleared. If it is greater than zero, the indirect flag 114 ** is set. Passing a value less than zero does not modify the current value 115 ** of the indirect flag, and may be used to query the current state of the 116 ** indirect flag for the specified session object. 117 ** 118 ** The return value indicates the final state of the indirect flag: 0 if 119 ** it is clear, or 1 if it is set. 120 */ 121 int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect); 122 123 /* 124 ** CAPI3REF: Attach A Table To A Session Object 125 ** 126 ** If argument zTab is not NULL, then it is the name of a table to attach 127 ** to the session object passed as the first argument. All subsequent changes 128 ** made to the table while the session object is enabled will be recorded. See 129 ** documentation for [sqlite3session_changeset()] for further details. 130 ** 131 ** Or, if argument zTab is NULL, then changes are recorded for all tables 132 ** in the database. If additional tables are added to the database (by 133 ** executing "CREATE TABLE" statements) after this call is made, changes for 134 ** the new tables are also recorded. 135 ** 136 ** Changes can only be recorded for tables that have a PRIMARY KEY explicitly 137 ** defined as part of their CREATE TABLE statement. It does not matter if the 138 ** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY 139 ** KEY may consist of a single column, or may be a composite key. 140 ** 141 ** It is not an error if the named table does not exist in the database. Nor 142 ** is it an error if the named table does not have a PRIMARY KEY. However, 143 ** no changes will be recorded in either of these scenarios. 144 ** 145 ** Changes are not recorded for individual rows that have NULL values stored 146 ** in one or more of their PRIMARY KEY columns. 147 ** 148 ** SQLITE_OK is returned if the call completes without error. Or, if an error 149 ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned. 150 */ 151 int sqlite3session_attach( 152 sqlite3_session *pSession, /* Session object */ 153 const char *zTab /* Table name */ 154 ); 155 156 /* 157 ** CAPI3REF: Set a table filter on a Session Object. 158 ** 159 ** The second argument (xFilter) is the "filter callback". For changes to rows 160 ** in tables that are not attached to the Session object, the filter is called 161 ** to determine whether changes to the table's rows should be tracked or not. 162 ** If xFilter returns 0, changes is not tracked. Note that once a table is 163 ** attached, xFilter will not be called again. 164 */ 165 void sqlite3session_table_filter( 166 sqlite3_session *pSession, /* Session object */ 167 int(*xFilter)( 168 void *pCtx, /* Copy of third arg to _filter_table() */ 169 const char *zTab /* Table name */ 170 ), 171 void *pCtx /* First argument passed to xFilter */ 172 ); 173 174 /* 175 ** CAPI3REF: Generate A Changeset From A Session Object 176 ** 177 ** Obtain a changeset containing changes to the tables attached to the 178 ** session object passed as the first argument. If successful, 179 ** set *ppChangeset to point to a buffer containing the changeset 180 ** and *pnChangeset to the size of the changeset in bytes before returning 181 ** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to 182 ** zero and return an SQLite error code. 183 ** 184 ** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes, 185 ** each representing a change to a single row of an attached table. An INSERT 186 ** change contains the values of each field of a new database row. A DELETE 187 ** contains the original values of each field of a deleted database row. An 188 ** UPDATE change contains the original values of each field of an updated 189 ** database row along with the updated values for each updated non-primary-key 190 ** column. It is not possible for an UPDATE change to represent a change that 191 ** modifies the values of primary key columns. If such a change is made, it 192 ** is represented in a changeset as a DELETE followed by an INSERT. 193 ** 194 ** Changes are not recorded for rows that have NULL values stored in one or 195 ** more of their PRIMARY KEY columns. If such a row is inserted or deleted, 196 ** no corresponding change is present in the changesets returned by this 197 ** function. If an existing row with one or more NULL values stored in 198 ** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL, 199 ** only an INSERT is appears in the changeset. Similarly, if an existing row 200 ** with non-NULL PRIMARY KEY values is updated so that one or more of its 201 ** PRIMARY KEY columns are set to NULL, the resulting changeset contains a 202 ** DELETE change only. 203 ** 204 ** The contents of a changeset may be traversed using an iterator created 205 ** using the [sqlite3changeset_start()] API. A changeset may be applied to 206 ** a database with a compatible schema using the [sqlite3changeset_apply()] 207 ** API. 208 ** 209 ** Within a changeset generated by this function, all changes related to a 210 ** single table are grouped together. In other words, when iterating through 211 ** a changeset or when applying a changeset to a database, all changes related 212 ** to a single table are processed before moving on to the next table. Tables 213 ** are sorted in the same order in which they were attached (or auto-attached) 214 ** to the sqlite3_session object. The order in which the changes related to 215 ** a single table are stored is undefined. 216 ** 217 ** Following a successful call to this function, it is the responsibility of 218 ** the caller to eventually free the buffer that *ppChangeset points to using 219 ** [sqlite3_free()]. 220 ** 221 ** <h3>Changeset Generation</h3> 222 ** 223 ** Once a table has been attached to a session object, the session object 224 ** records the primary key values of all new rows inserted into the table. 225 ** It also records the original primary key and other column values of any 226 ** deleted or updated rows. For each unique primary key value, data is only 227 ** recorded once - the first time a row with said primary key is inserted, 228 ** updated or deleted in the lifetime of the session. 229 ** 230 ** There is one exception to the previous paragraph: when a row is inserted, 231 ** updated or deleted, if one or more of its primary key columns contain a 232 ** NULL value, no record of the change is made. 233 ** 234 ** The session object therefore accumulates two types of records - those 235 ** that consist of primary key values only (created when the user inserts 236 ** a new record) and those that consist of the primary key values and the 237 ** original values of other table columns (created when the users deletes 238 ** or updates a record). 239 ** 240 ** When this function is called, the requested changeset is created using 241 ** both the accumulated records and the current contents of the database 242 ** file. Specifically: 243 ** 244 ** <ul> 245 ** <li> For each record generated by an insert, the database is queried 246 ** for a row with a matching primary key. If one is found, an INSERT 247 ** change is added to the changeset. If no such row is found, no change 248 ** is added to the changeset. 249 ** 250 ** <li> For each record generated by an update or delete, the database is 251 ** queried for a row with a matching primary key. If such a row is 252 ** found and one or more of the non-primary key fields have been 253 ** modified from their original values, an UPDATE change is added to 254 ** the changeset. Or, if no such row is found in the table, a DELETE 255 ** change is added to the changeset. If there is a row with a matching 256 ** primary key in the database, but all fields contain their original 257 ** values, no change is added to the changeset. 258 ** </ul> 259 ** 260 ** This means, amongst other things, that if a row is inserted and then later 261 ** deleted while a session object is active, neither the insert nor the delete 262 ** will be present in the changeset. Or if a row is deleted and then later a 263 ** row with the same primary key values inserted while a session object is 264 ** active, the resulting changeset will contain an UPDATE change instead of 265 ** a DELETE and an INSERT. 266 ** 267 ** When a session object is disabled (see the [sqlite3session_enable()] API), 268 ** it does not accumulate records when rows are inserted, updated or deleted. 269 ** This may appear to have some counter-intuitive effects if a single row 270 ** is written to more than once during a session. For example, if a row 271 ** is inserted while a session object is enabled, then later deleted while 272 ** the same session object is disabled, no INSERT record will appear in the 273 ** changeset, even though the delete took place while the session was disabled. 274 ** Or, if one field of a row is updated while a session is disabled, and 275 ** another field of the same row is updated while the session is enabled, the 276 ** resulting changeset will contain an UPDATE change that updates both fields. 277 */ 278 int sqlite3session_changeset( 279 sqlite3_session *pSession, /* Session object */ 280 int *pnChangeset, /* OUT: Size of buffer at *ppChangeset */ 281 void **ppChangeset /* OUT: Buffer containing changeset */ 282 ); 283 284 /* 285 ** CAPI3REF: Load The Difference Between Tables Into A Session 286 ** 287 ** If it is not already attached to the session object passed as the first 288 ** argument, this function attaches table zTbl in the same manner as the 289 ** [sqlite3session_attach()] function. If zTbl does not exist, or if it 290 ** does not have a primary key, this function is a no-op (but does not return 291 ** an error). 292 ** 293 ** Argument zFromDb must be the name of a database ("main", "temp" etc.) 294 ** attached to the same database handle as the session object that contains 295 ** a table compatible with the table attached to the session by this function. 296 ** A table is considered compatible if it: 297 ** 298 ** <ul> 299 ** <li> Has the same name, 300 ** <li> Has the same set of columns declared in the same order, and 301 ** <li> Has the same PRIMARY KEY definition. 302 ** </ul> 303 ** 304 ** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables 305 ** are compatible but do not have any PRIMARY KEY columns, it is not an error 306 ** but no changes are added to the session object. As with other session 307 ** APIs, tables without PRIMARY KEYs are simply ignored. 308 ** 309 ** This function adds a set of changes to the session object that could be 310 ** used to update the table in database zFrom (call this the "from-table") 311 ** so that its content is the same as the table attached to the session 312 ** object (call this the "to-table"). Specifically: 313 ** 314 ** <ul> 315 ** <li> For each row (primary key) that exists in the to-table but not in 316 ** the from-table, an INSERT record is added to the session object. 317 ** 318 ** <li> For each row (primary key) that exists in the to-table but not in 319 ** the from-table, a DELETE record is added to the session object. 320 ** 321 ** <li> For each row (primary key) that exists in both tables, but features 322 ** different non-PK values in each, an UPDATE record is added to the 323 ** session. 324 ** </ul> 325 ** 326 ** To clarify, if this function is called and then a changeset constructed 327 ** using [sqlite3session_changeset()], then after applying that changeset to 328 ** database zFrom the contents of the two compatible tables would be 329 ** identical. 330 ** 331 ** It an error if database zFrom does not exist or does not contain the 332 ** required compatible table. 333 ** 334 ** If the operation successful, SQLITE_OK is returned. Otherwise, an SQLite 335 ** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg 336 ** may be set to point to a buffer containing an English language error 337 ** message. It is the responsibility of the caller to free this buffer using 338 ** sqlite3_free(). 339 */ 340 int sqlite3session_diff( 341 sqlite3_session *pSession, 342 const char *zFromDb, 343 const char *zTbl, 344 char **pzErrMsg 345 ); 346 347 348 /* 349 ** CAPI3REF: Generate A Patchset From A Session Object 350 ** 351 ** The differences between a patchset and a changeset are that: 352 ** 353 ** <ul> 354 ** <li> DELETE records consist of the primary key fields only. The 355 ** original values of other fields are omitted. 356 ** <li> The original values of any modified fields are omitted from 357 ** UPDATE records. 358 ** </ul> 359 ** 360 ** A patchset blob may be used with up to date versions of all 361 ** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(), 362 ** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly, 363 ** attempting to use a patchset blob with old versions of the 364 ** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error. 365 ** 366 ** Because the non-primary key "old.*" fields are omitted, no 367 ** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset 368 ** is passed to the sqlite3changeset_apply() API. Other conflict types work 369 ** in the same way as for changesets. 370 ** 371 ** Changes within a patchset are ordered in the same way as for changesets 372 ** generated by the sqlite3session_changeset() function (i.e. all changes for 373 ** a single table are grouped together, tables appear in the order in which 374 ** they were attached to the session object). 375 */ 376 int sqlite3session_patchset( 377 sqlite3_session *pSession, /* Session object */ 378 int *pnPatchset, /* OUT: Size of buffer at *ppChangeset */ 379 void **ppPatchset /* OUT: Buffer containing changeset */ 380 ); 381 382 /* 383 ** CAPI3REF: Test if a changeset has recorded any changes. 384 ** 385 ** Return non-zero if no changes to attached tables have been recorded by 386 ** the session object passed as the first argument. Otherwise, if one or 387 ** more changes have been recorded, return zero. 388 ** 389 ** Even if this function returns zero, it is possible that calling 390 ** [sqlite3session_changeset()] on the session handle may still return a 391 ** changeset that contains no changes. This can happen when a row in 392 ** an attached table is modified and then later on the original values 393 ** are restored. However, if this function returns non-zero, then it is 394 ** guaranteed that a call to sqlite3session_changeset() will return a 395 ** changeset containing zero changes. 396 */ 397 int sqlite3session_isempty(sqlite3_session *pSession); 398 399 /* 400 ** CAPI3REF: Create An Iterator To Traverse A Changeset 401 ** 402 ** Create an iterator used to iterate through the contents of a changeset. 403 ** If successful, *pp is set to point to the iterator handle and SQLITE_OK 404 ** is returned. Otherwise, if an error occurs, *pp is set to zero and an 405 ** SQLite error code is returned. 406 ** 407 ** The following functions can be used to advance and query a changeset 408 ** iterator created by this function: 409 ** 410 ** <ul> 411 ** <li> [sqlite3changeset_next()] 412 ** <li> [sqlite3changeset_op()] 413 ** <li> [sqlite3changeset_new()] 414 ** <li> [sqlite3changeset_old()] 415 ** </ul> 416 ** 417 ** It is the responsibility of the caller to eventually destroy the iterator 418 ** by passing it to [sqlite3changeset_finalize()]. The buffer containing the 419 ** changeset (pChangeset) must remain valid until after the iterator is 420 ** destroyed. 421 ** 422 ** Assuming the changeset blob was created by one of the 423 ** [sqlite3session_changeset()], [sqlite3changeset_concat()] or 424 ** [sqlite3changeset_invert()] functions, all changes within the changeset 425 ** that apply to a single table are grouped together. This means that when 426 ** an application iterates through a changeset using an iterator created by 427 ** this function, all changes that relate to a single table are visited 428 ** consecutively. There is no chance that the iterator will visit a change 429 ** the applies to table X, then one for table Y, and then later on visit 430 ** another change for table X. 431 */ 432 int sqlite3changeset_start( 433 sqlite3_changeset_iter **pp, /* OUT: New changeset iterator handle */ 434 int nChangeset, /* Size of changeset blob in bytes */ 435 void *pChangeset /* Pointer to blob containing changeset */ 436 ); 437 438 439 /* 440 ** CAPI3REF: Advance A Changeset Iterator 441 ** 442 ** This function may only be used with iterators created by function 443 ** [sqlite3changeset_start()]. If it is called on an iterator passed to 444 ** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE 445 ** is returned and the call has no effect. 446 ** 447 ** Immediately after an iterator is created by sqlite3changeset_start(), it 448 ** does not point to any change in the changeset. Assuming the changeset 449 ** is not empty, the first call to this function advances the iterator to 450 ** point to the first change in the changeset. Each subsequent call advances 451 ** the iterator to point to the next change in the changeset (if any). If 452 ** no error occurs and the iterator points to a valid change after a call 453 ** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned. 454 ** Otherwise, if all changes in the changeset have already been visited, 455 ** SQLITE_DONE is returned. 456 ** 457 ** If an error occurs, an SQLite error code is returned. Possible error 458 ** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or 459 ** SQLITE_NOMEM. 460 */ 461 int sqlite3changeset_next(sqlite3_changeset_iter *pIter); 462 463 /* 464 ** CAPI3REF: Obtain The Current Operation From A Changeset Iterator 465 ** 466 ** The pIter argument passed to this function may either be an iterator 467 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator 468 ** created by [sqlite3changeset_start()]. In the latter case, the most recent 469 ** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this 470 ** is not the case, this function returns [SQLITE_MISUSE]. 471 ** 472 ** If argument pzTab is not NULL, then *pzTab is set to point to a 473 ** nul-terminated utf-8 encoded string containing the name of the table 474 ** affected by the current change. The buffer remains valid until either 475 ** sqlite3changeset_next() is called on the iterator or until the 476 ** conflict-handler function returns. If pnCol is not NULL, then *pnCol is 477 ** set to the number of columns in the table affected by the change. If 478 ** pbIncorrect is not NULL, then *pbIndirect is set to true (1) if the change 479 ** is an indirect change, or false (0) otherwise. See the documentation for 480 ** [sqlite3session_indirect()] for a description of direct and indirect 481 ** changes. Finally, if pOp is not NULL, then *pOp is set to one of 482 ** [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE], depending on the 483 ** type of change that the iterator currently points to. 484 ** 485 ** If no error occurs, SQLITE_OK is returned. If an error does occur, an 486 ** SQLite error code is returned. The values of the output variables may not 487 ** be trusted in this case. 488 */ 489 int sqlite3changeset_op( 490 sqlite3_changeset_iter *pIter, /* Iterator object */ 491 const char **pzTab, /* OUT: Pointer to table name */ 492 int *pnCol, /* OUT: Number of columns in table */ 493 int *pOp, /* OUT: SQLITE_INSERT, DELETE or UPDATE */ 494 int *pbIndirect /* OUT: True for an 'indirect' change */ 495 ); 496 497 /* 498 ** CAPI3REF: Obtain The Primary Key Definition Of A Table 499 ** 500 ** For each modified table, a changeset includes the following: 501 ** 502 ** <ul> 503 ** <li> The number of columns in the table, and 504 ** <li> Which of those columns make up the tables PRIMARY KEY. 505 ** </ul> 506 ** 507 ** This function is used to find which columns comprise the PRIMARY KEY of 508 ** the table modified by the change that iterator pIter currently points to. 509 ** If successful, *pabPK is set to point to an array of nCol entries, where 510 ** nCol is the number of columns in the table. Elements of *pabPK are set to 511 ** 0x01 if the corresponding column is part of the tables primary key, or 512 ** 0x00 if it is not. 513 ** 514 ** If argument pnCol is not NULL, then *pnCol is set to the number of columns 515 ** in the table. 516 ** 517 ** If this function is called when the iterator does not point to a valid 518 ** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise, 519 ** SQLITE_OK is returned and the output variables populated as described 520 ** above. 521 */ 522 int sqlite3changeset_pk( 523 sqlite3_changeset_iter *pIter, /* Iterator object */ 524 unsigned char **pabPK, /* OUT: Array of boolean - true for PK cols */ 525 int *pnCol /* OUT: Number of entries in output array */ 526 ); 527 528 /* 529 ** CAPI3REF: Obtain old.* Values From A Changeset Iterator 530 ** 531 ** The pIter argument passed to this function may either be an iterator 532 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator 533 ** created by [sqlite3changeset_start()]. In the latter case, the most recent 534 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW. 535 ** Furthermore, it may only be called if the type of change that the iterator 536 ** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise, 537 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL. 538 ** 539 ** Argument iVal must be greater than or equal to 0, and less than the number 540 ** of columns in the table affected by the current change. Otherwise, 541 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL. 542 ** 543 ** If successful, this function sets *ppValue to point to a protected 544 ** sqlite3_value object containing the iVal'th value from the vector of 545 ** original row values stored as part of the UPDATE or DELETE change and 546 ** returns SQLITE_OK. The name of the function comes from the fact that this 547 ** is similar to the "old.*" columns available to update or delete triggers. 548 ** 549 ** If some other error occurs (e.g. an OOM condition), an SQLite error code 550 ** is returned and *ppValue is set to NULL. 551 */ 552 int sqlite3changeset_old( 553 sqlite3_changeset_iter *pIter, /* Changeset iterator */ 554 int iVal, /* Column number */ 555 sqlite3_value **ppValue /* OUT: Old value (or NULL pointer) */ 556 ); 557 558 /* 559 ** CAPI3REF: Obtain new.* Values From A Changeset Iterator 560 ** 561 ** The pIter argument passed to this function may either be an iterator 562 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator 563 ** created by [sqlite3changeset_start()]. In the latter case, the most recent 564 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW. 565 ** Furthermore, it may only be called if the type of change that the iterator 566 ** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise, 567 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL. 568 ** 569 ** Argument iVal must be greater than or equal to 0, and less than the number 570 ** of columns in the table affected by the current change. Otherwise, 571 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL. 572 ** 573 ** If successful, this function sets *ppValue to point to a protected 574 ** sqlite3_value object containing the iVal'th value from the vector of 575 ** new row values stored as part of the UPDATE or INSERT change and 576 ** returns SQLITE_OK. If the change is an UPDATE and does not include 577 ** a new value for the requested column, *ppValue is set to NULL and 578 ** SQLITE_OK returned. The name of the function comes from the fact that 579 ** this is similar to the "new.*" columns available to update or delete 580 ** triggers. 581 ** 582 ** If some other error occurs (e.g. an OOM condition), an SQLite error code 583 ** is returned and *ppValue is set to NULL. 584 */ 585 int sqlite3changeset_new( 586 sqlite3_changeset_iter *pIter, /* Changeset iterator */ 587 int iVal, /* Column number */ 588 sqlite3_value **ppValue /* OUT: New value (or NULL pointer) */ 589 ); 590 591 /* 592 ** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator 593 ** 594 ** This function should only be used with iterator objects passed to a 595 ** conflict-handler callback by [sqlite3changeset_apply()] with either 596 ** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function 597 ** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue 598 ** is set to NULL. 599 ** 600 ** Argument iVal must be greater than or equal to 0, and less than the number 601 ** of columns in the table affected by the current change. Otherwise, 602 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL. 603 ** 604 ** If successful, this function sets *ppValue to point to a protected 605 ** sqlite3_value object containing the iVal'th value from the 606 ** "conflicting row" associated with the current conflict-handler callback 607 ** and returns SQLITE_OK. 608 ** 609 ** If some other error occurs (e.g. an OOM condition), an SQLite error code 610 ** is returned and *ppValue is set to NULL. 611 */ 612 int sqlite3changeset_conflict( 613 sqlite3_changeset_iter *pIter, /* Changeset iterator */ 614 int iVal, /* Column number */ 615 sqlite3_value **ppValue /* OUT: Value from conflicting row */ 616 ); 617 618 /* 619 ** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations 620 ** 621 ** This function may only be called with an iterator passed to an 622 ** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case 623 ** it sets the output variable to the total number of known foreign key 624 ** violations in the destination database and returns SQLITE_OK. 625 ** 626 ** In all other cases this function returns SQLITE_MISUSE. 627 */ 628 int sqlite3changeset_fk_conflicts( 629 sqlite3_changeset_iter *pIter, /* Changeset iterator */ 630 int *pnOut /* OUT: Number of FK violations */ 631 ); 632 633 634 /* 635 ** CAPI3REF: Finalize A Changeset Iterator 636 ** 637 ** This function is used to finalize an iterator allocated with 638 ** [sqlite3changeset_start()]. 639 ** 640 ** This function should only be called on iterators created using the 641 ** [sqlite3changeset_start()] function. If an application calls this 642 ** function with an iterator passed to a conflict-handler by 643 ** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the 644 ** call has no effect. 645 ** 646 ** If an error was encountered within a call to an sqlite3changeset_xxx() 647 ** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an 648 ** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding 649 ** to that error is returned by this function. Otherwise, SQLITE_OK is 650 ** returned. This is to allow the following pattern (pseudo-code): 651 ** 652 ** sqlite3changeset_start(); 653 ** while( SQLITE_ROW==sqlite3changeset_next() ){ 654 ** // Do something with change. 655 ** } 656 ** rc = sqlite3changeset_finalize(); 657 ** if( rc!=SQLITE_OK ){ 658 ** // An error has occurred 659 ** } 660 */ 661 int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter); 662 663 /* 664 ** CAPI3REF: Invert A Changeset 665 ** 666 ** This function is used to "invert" a changeset object. Applying an inverted 667 ** changeset to a database reverses the effects of applying the uninverted 668 ** changeset. Specifically: 669 ** 670 ** <ul> 671 ** <li> Each DELETE change is changed to an INSERT, and 672 ** <li> Each INSERT change is changed to a DELETE, and 673 ** <li> For each UPDATE change, the old.* and new.* values are exchanged. 674 ** </ul> 675 ** 676 ** This function does not change the order in which changes appear within 677 ** the changeset. It merely reverses the sense of each individual change. 678 ** 679 ** If successful, a pointer to a buffer containing the inverted changeset 680 ** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and 681 ** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are 682 ** zeroed and an SQLite error code returned. 683 ** 684 ** It is the responsibility of the caller to eventually call sqlite3_free() 685 ** on the *ppOut pointer to free the buffer allocation following a successful 686 ** call to this function. 687 ** 688 ** WARNING/TODO: This function currently assumes that the input is a valid 689 ** changeset. If it is not, the results are undefined. 690 */ 691 int sqlite3changeset_invert( 692 int nIn, const void *pIn, /* Input changeset */ 693 int *pnOut, void **ppOut /* OUT: Inverse of input */ 694 ); 695 696 /* 697 ** CAPI3REF: Concatenate Two Changeset Objects 698 ** 699 ** This function is used to concatenate two changesets, A and B, into a 700 ** single changeset. The result is a changeset equivalent to applying 701 ** changeset A followed by changeset B. 702 ** 703 ** This function combines the two input changesets using an 704 ** sqlite3_changegroup object. Calling it produces similar results as the 705 ** following code fragment: 706 ** 707 ** sqlite3_changegroup *pGrp; 708 ** rc = sqlite3_changegroup_new(&pGrp); 709 ** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA); 710 ** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB); 711 ** if( rc==SQLITE_OK ){ 712 ** rc = sqlite3changegroup_output(pGrp, pnOut, ppOut); 713 ** }else{ 714 ** *ppOut = 0; 715 ** *pnOut = 0; 716 ** } 717 ** 718 ** Refer to the sqlite3_changegroup documentation below for details. 719 */ 720 int sqlite3changeset_concat( 721 int nA, /* Number of bytes in buffer pA */ 722 void *pA, /* Pointer to buffer containing changeset A */ 723 int nB, /* Number of bytes in buffer pB */ 724 void *pB, /* Pointer to buffer containing changeset B */ 725 int *pnOut, /* OUT: Number of bytes in output changeset */ 726 void **ppOut /* OUT: Buffer containing output changeset */ 727 ); 728 729 730 /* 731 ** CAPI3REF: Changegroup Handle 732 */ 733 typedef struct sqlite3_changegroup sqlite3_changegroup; 734 735 /* 736 ** CAPI3REF: Create A New Changegroup Object 737 ** 738 ** An sqlite3_changegroup object is used to combine two or more changesets 739 ** (or patchsets) into a single changeset (or patchset). A single changegroup 740 ** object may combine changesets or patchsets, but not both. The output is 741 ** always in the same format as the input. 742 ** 743 ** If successful, this function returns SQLITE_OK and populates (*pp) with 744 ** a pointer to a new sqlite3_changegroup object before returning. The caller 745 ** should eventually free the returned object using a call to 746 ** sqlite3changegroup_delete(). If an error occurs, an SQLite error code 747 ** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL. 748 ** 749 ** The usual usage pattern for an sqlite3_changegroup object is as follows: 750 ** 751 ** <ul> 752 ** <li> It is created using a call to sqlite3changegroup_new(). 753 ** 754 ** <li> Zero or more changesets (or patchsets) are added to the object 755 ** by calling sqlite3changegroup_add(). 756 ** 757 ** <li> The result of combining all input changesets together is obtained 758 ** by the application via a call to sqlite3changegroup_output(). 759 ** 760 ** <li> The object is deleted using a call to sqlite3changegroup_delete(). 761 ** </ul> 762 ** 763 ** Any number of calls to add() and output() may be made between the calls to 764 ** new() and delete(), and in any order. 765 ** 766 ** As well as the regular sqlite3changegroup_add() and 767 ** sqlite3changegroup_output() functions, also available are the streaming 768 ** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm(). 769 */ 770 int sqlite3changegroup_new(sqlite3_changegroup **pp); 771 772 /* 773 ** CAPI3REF: Add A Changeset To A Changegroup 774 ** 775 ** Add all changes within the changeset (or patchset) in buffer pData (size 776 ** nData bytes) to the changegroup. 777 ** 778 ** If the buffer contains a patchset, then all prior calls to this function 779 ** on the same changegroup object must also have specified patchsets. Or, if 780 ** the buffer contains a changeset, so must have the earlier calls to this 781 ** function. Otherwise, SQLITE_ERROR is returned and no changes are added 782 ** to the changegroup. 783 ** 784 ** Rows within the changeset and changegroup are identified by the values in 785 ** their PRIMARY KEY columns. A change in the changeset is considered to 786 ** apply to the same row as a change already present in the changegroup if 787 ** the two rows have the same primary key. 788 ** 789 ** Changes to rows that do not already appear in the changegroup are 790 ** simply copied into it. Or, if both the new changeset and the changegroup 791 ** contain changes that apply to a single row, the final contents of the 792 ** changegroup depends on the type of each change, as follows: 793 ** 794 ** <table border=1 style="margin-left:8ex;margin-right:8ex"> 795 ** <tr><th style="white-space:pre">Existing Change </th> 796 ** <th style="white-space:pre">New Change </th> 797 ** <th>Output Change 798 ** <tr><td>INSERT <td>INSERT <td> 799 ** The new change is ignored. This case does not occur if the new 800 ** changeset was recorded immediately after the changesets already 801 ** added to the changegroup. 802 ** <tr><td>INSERT <td>UPDATE <td> 803 ** The INSERT change remains in the changegroup. The values in the 804 ** INSERT change are modified as if the row was inserted by the 805 ** existing change and then updated according to the new change. 806 ** <tr><td>INSERT <td>DELETE <td> 807 ** The existing INSERT is removed from the changegroup. The DELETE is 808 ** not added. 809 ** <tr><td>UPDATE <td>INSERT <td> 810 ** The new change is ignored. This case does not occur if the new 811 ** changeset was recorded immediately after the changesets already 812 ** added to the changegroup. 813 ** <tr><td>UPDATE <td>UPDATE <td> 814 ** The existing UPDATE remains within the changegroup. It is amended 815 ** so that the accompanying values are as if the row was updated once 816 ** by the existing change and then again by the new change. 817 ** <tr><td>UPDATE <td>DELETE <td> 818 ** The existing UPDATE is replaced by the new DELETE within the 819 ** changegroup. 820 ** <tr><td>DELETE <td>INSERT <td> 821 ** If one or more of the column values in the row inserted by the 822 ** new change differ from those in the row deleted by the existing 823 ** change, the existing DELETE is replaced by an UPDATE within the 824 ** changegroup. Otherwise, if the inserted row is exactly the same 825 ** as the deleted row, the existing DELETE is simply discarded. 826 ** <tr><td>DELETE <td>UPDATE <td> 827 ** The new change is ignored. This case does not occur if the new 828 ** changeset was recorded immediately after the changesets already 829 ** added to the changegroup. 830 ** <tr><td>DELETE <td>DELETE <td> 831 ** The new change is ignored. This case does not occur if the new 832 ** changeset was recorded immediately after the changesets already 833 ** added to the changegroup. 834 ** </table> 835 ** 836 ** If the new changeset contains changes to a table that is already present 837 ** in the changegroup, then the number of columns and the position of the 838 ** primary key columns for the table must be consistent. If this is not the 839 ** case, this function fails with SQLITE_SCHEMA. If the input changeset 840 ** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is 841 ** returned. Or, if an out-of-memory condition occurs during processing, this 842 ** function returns SQLITE_NOMEM. In all cases, if an error occurs the 843 ** final contents of the changegroup is undefined. 844 ** 845 ** If no error occurs, SQLITE_OK is returned. 846 */ 847 int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData); 848 849 /* 850 ** CAPI3REF: Obtain A Composite Changeset From A Changegroup 851 ** 852 ** Obtain a buffer containing a changeset (or patchset) representing the 853 ** current contents of the changegroup. If the inputs to the changegroup 854 ** were themselves changesets, the output is a changeset. Or, if the 855 ** inputs were patchsets, the output is also a patchset. 856 ** 857 ** As with the output of the sqlite3session_changeset() and 858 ** sqlite3session_patchset() functions, all changes related to a single 859 ** table are grouped together in the output of this function. Tables appear 860 ** in the same order as for the very first changeset added to the changegroup. 861 ** If the second or subsequent changesets added to the changegroup contain 862 ** changes for tables that do not appear in the first changeset, they are 863 ** appended onto the end of the output changeset, again in the order in 864 ** which they are first encountered. 865 ** 866 ** If an error occurs, an SQLite error code is returned and the output 867 ** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK 868 ** is returned and the output variables are set to the size of and a 869 ** pointer to the output buffer, respectively. In this case it is the 870 ** responsibility of the caller to eventually free the buffer using a 871 ** call to sqlite3_free(). 872 */ 873 int sqlite3changegroup_output( 874 sqlite3_changegroup*, 875 int *pnData, /* OUT: Size of output buffer in bytes */ 876 void **ppData /* OUT: Pointer to output buffer */ 877 ); 878 879 /* 880 ** CAPI3REF: Delete A Changegroup Object 881 */ 882 void sqlite3changegroup_delete(sqlite3_changegroup*); 883 884 /* 885 ** CAPI3REF: Apply A Changeset To A Database 886 ** 887 ** Apply a changeset to a database. This function attempts to update the 888 ** "main" database attached to handle db with the changes found in the 889 ** changeset passed via the second and third arguments. 890 ** 891 ** The fourth argument (xFilter) passed to this function is the "filter 892 ** callback". If it is not NULL, then for each table affected by at least one 893 ** change in the changeset, the filter callback is invoked with 894 ** the table name as the second argument, and a copy of the context pointer 895 ** passed as the sixth argument to this function as the first. If the "filter 896 ** callback" returns zero, then no attempt is made to apply any changes to 897 ** the table. Otherwise, if the return value is non-zero or the xFilter 898 ** argument to this function is NULL, all changes related to the table are 899 ** attempted. 900 ** 901 ** For each table that is not excluded by the filter callback, this function 902 ** tests that the target database contains a compatible table. A table is 903 ** considered compatible if all of the following are true: 904 ** 905 ** <ul> 906 ** <li> The table has the same name as the name recorded in the 907 ** changeset, and 908 ** <li> The table has at least as many columns as recorded in the 909 ** changeset, and 910 ** <li> The table has primary key columns in the same position as 911 ** recorded in the changeset. 912 ** </ul> 913 ** 914 ** If there is no compatible table, it is not an error, but none of the 915 ** changes associated with the table are applied. A warning message is issued 916 ** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most 917 ** one such warning is issued for each table in the changeset. 918 ** 919 ** For each change for which there is a compatible table, an attempt is made 920 ** to modify the table contents according to the UPDATE, INSERT or DELETE 921 ** change. If a change cannot be applied cleanly, the conflict handler 922 ** function passed as the fifth argument to sqlite3changeset_apply() may be 923 ** invoked. A description of exactly when the conflict handler is invoked for 924 ** each type of change is below. 925 ** 926 ** Unlike the xFilter argument, xConflict may not be passed NULL. The results 927 ** of passing anything other than a valid function pointer as the xConflict 928 ** argument are undefined. 929 ** 930 ** Each time the conflict handler function is invoked, it must return one 931 ** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or 932 ** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned 933 ** if the second argument passed to the conflict handler is either 934 ** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler 935 ** returns an illegal value, any changes already made are rolled back and 936 ** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different 937 ** actions are taken by sqlite3changeset_apply() depending on the value 938 ** returned by each invocation of the conflict-handler function. Refer to 939 ** the documentation for the three 940 ** [SQLITE_CHANGESET_OMIT|available return values] for details. 941 ** 942 ** <dl> 943 ** <dt>DELETE Changes<dd> 944 ** For each DELETE change, this function checks if the target database 945 ** contains a row with the same primary key value (or values) as the 946 ** original row values stored in the changeset. If it does, and the values 947 ** stored in all non-primary key columns also match the values stored in 948 ** the changeset the row is deleted from the target database. 949 ** 950 ** If a row with matching primary key values is found, but one or more of 951 ** the non-primary key fields contains a value different from the original 952 ** row value stored in the changeset, the conflict-handler function is 953 ** invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the 954 ** database table has more columns than are recorded in the changeset, 955 ** only the values of those non-primary key fields are compared against 956 ** the current database contents - any trailing database table columns 957 ** are ignored. 958 ** 959 ** If no row with matching primary key values is found in the database, 960 ** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND] 961 ** passed as the second argument. 962 ** 963 ** If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT 964 ** (which can only happen if a foreign key constraint is violated), the 965 ** conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT] 966 ** passed as the second argument. This includes the case where the DELETE 967 ** operation is attempted because an earlier call to the conflict handler 968 ** function returned [SQLITE_CHANGESET_REPLACE]. 969 ** 970 ** <dt>INSERT Changes<dd> 971 ** For each INSERT change, an attempt is made to insert the new row into 972 ** the database. If the changeset row contains fewer fields than the 973 ** database table, the trailing fields are populated with their default 974 ** values. 975 ** 976 ** If the attempt to insert the row fails because the database already 977 ** contains a row with the same primary key values, the conflict handler 978 ** function is invoked with the second argument set to 979 ** [SQLITE_CHANGESET_CONFLICT]. 980 ** 981 ** If the attempt to insert the row fails because of some other constraint 982 ** violation (e.g. NOT NULL or UNIQUE), the conflict handler function is 983 ** invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT]. 984 ** This includes the case where the INSERT operation is re-attempted because 985 ** an earlier call to the conflict handler function returned 986 ** [SQLITE_CHANGESET_REPLACE]. 987 ** 988 ** <dt>UPDATE Changes<dd> 989 ** For each UPDATE change, this function checks if the target database 990 ** contains a row with the same primary key value (or values) as the 991 ** original row values stored in the changeset. If it does, and the values 992 ** stored in all modified non-primary key columns also match the values 993 ** stored in the changeset the row is updated within the target database. 994 ** 995 ** If a row with matching primary key values is found, but one or more of 996 ** the modified non-primary key fields contains a value different from an 997 ** original row value stored in the changeset, the conflict-handler function 998 ** is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since 999 ** UPDATE changes only contain values for non-primary key fields that are 1000 ** to be modified, only those fields need to match the original values to 1001 ** avoid the SQLITE_CHANGESET_DATA conflict-handler callback. 1002 ** 1003 ** If no row with matching primary key values is found in the database, 1004 ** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND] 1005 ** passed as the second argument. 1006 ** 1007 ** If the UPDATE operation is attempted, but SQLite returns 1008 ** SQLITE_CONSTRAINT, the conflict-handler function is invoked with 1009 ** [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument. 1010 ** This includes the case where the UPDATE operation is attempted after 1011 ** an earlier call to the conflict handler function returned 1012 ** [SQLITE_CHANGESET_REPLACE]. 1013 ** </dl> 1014 ** 1015 ** It is safe to execute SQL statements, including those that write to the 1016 ** table that the callback related to, from within the xConflict callback. 1017 ** This can be used to further customize the applications conflict 1018 ** resolution strategy. 1019 ** 1020 ** All changes made by this function are enclosed in a savepoint transaction. 1021 ** If any other error (aside from a constraint failure when attempting to 1022 ** write to the target database) occurs, then the savepoint transaction is 1023 ** rolled back, restoring the target database to its original state, and an 1024 ** SQLite error code returned. 1025 */ 1026 int sqlite3changeset_apply( 1027 sqlite3 *db, /* Apply change to "main" db of this handle */ 1028 int nChangeset, /* Size of changeset in bytes */ 1029 void *pChangeset, /* Changeset blob */ 1030 int(*xFilter)( 1031 void *pCtx, /* Copy of sixth arg to _apply() */ 1032 const char *zTab /* Table name */ 1033 ), 1034 int(*xConflict)( 1035 void *pCtx, /* Copy of sixth arg to _apply() */ 1036 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */ 1037 sqlite3_changeset_iter *p /* Handle describing change and conflict */ 1038 ), 1039 void *pCtx /* First argument passed to xConflict */ 1040 ); 1041 1042 /* 1043 ** CAPI3REF: Constants Passed To The Conflict Handler 1044 ** 1045 ** Values that may be passed as the second argument to a conflict-handler. 1046 ** 1047 ** <dl> 1048 ** <dt>SQLITE_CHANGESET_DATA<dd> 1049 ** The conflict handler is invoked with CHANGESET_DATA as the second argument 1050 ** when processing a DELETE or UPDATE change if a row with the required 1051 ** PRIMARY KEY fields is present in the database, but one or more other 1052 ** (non primary-key) fields modified by the update do not contain the 1053 ** expected "before" values. 1054 ** 1055 ** The conflicting row, in this case, is the database row with the matching 1056 ** primary key. 1057 ** 1058 ** <dt>SQLITE_CHANGESET_NOTFOUND<dd> 1059 ** The conflict handler is invoked with CHANGESET_NOTFOUND as the second 1060 ** argument when processing a DELETE or UPDATE change if a row with the 1061 ** required PRIMARY KEY fields is not present in the database. 1062 ** 1063 ** There is no conflicting row in this case. The results of invoking the 1064 ** sqlite3changeset_conflict() API are undefined. 1065 ** 1066 ** <dt>SQLITE_CHANGESET_CONFLICT<dd> 1067 ** CHANGESET_CONFLICT is passed as the second argument to the conflict 1068 ** handler while processing an INSERT change if the operation would result 1069 ** in duplicate primary key values. 1070 ** 1071 ** The conflicting row in this case is the database row with the matching 1072 ** primary key. 1073 ** 1074 ** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd> 1075 ** If foreign key handling is enabled, and applying a changeset leaves the 1076 ** database in a state containing foreign key violations, the conflict 1077 ** handler is invoked with CHANGESET_FOREIGN_KEY as the second argument 1078 ** exactly once before the changeset is committed. If the conflict handler 1079 ** returns CHANGESET_OMIT, the changes, including those that caused the 1080 ** foreign key constraint violation, are committed. Or, if it returns 1081 ** CHANGESET_ABORT, the changeset is rolled back. 1082 ** 1083 ** No current or conflicting row information is provided. The only function 1084 ** it is possible to call on the supplied sqlite3_changeset_iter handle 1085 ** is sqlite3changeset_fk_conflicts(). 1086 ** 1087 ** <dt>SQLITE_CHANGESET_CONSTRAINT<dd> 1088 ** If any other constraint violation occurs while applying a change (i.e. 1089 ** a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is 1090 ** invoked with CHANGESET_CONSTRAINT as the second argument. 1091 ** 1092 ** There is no conflicting row in this case. The results of invoking the 1093 ** sqlite3changeset_conflict() API are undefined. 1094 ** 1095 ** </dl> 1096 */ 1097 #define SQLITE_CHANGESET_DATA 1 1098 #define SQLITE_CHANGESET_NOTFOUND 2 1099 #define SQLITE_CHANGESET_CONFLICT 3 1100 #define SQLITE_CHANGESET_CONSTRAINT 4 1101 #define SQLITE_CHANGESET_FOREIGN_KEY 5 1102 1103 /* 1104 ** CAPI3REF: Constants Returned By The Conflict Handler 1105 ** 1106 ** A conflict handler callback must return one of the following three values. 1107 ** 1108 ** <dl> 1109 ** <dt>SQLITE_CHANGESET_OMIT<dd> 1110 ** If a conflict handler returns this value no special action is taken. The 1111 ** change that caused the conflict is not applied. The session module 1112 ** continues to the next change in the changeset. 1113 ** 1114 ** <dt>SQLITE_CHANGESET_REPLACE<dd> 1115 ** This value may only be returned if the second argument to the conflict 1116 ** handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this 1117 ** is not the case, any changes applied so far are rolled back and the 1118 ** call to sqlite3changeset_apply() returns SQLITE_MISUSE. 1119 ** 1120 ** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict 1121 ** handler, then the conflicting row is either updated or deleted, depending 1122 ** on the type of change. 1123 ** 1124 ** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict 1125 ** handler, then the conflicting row is removed from the database and a 1126 ** second attempt to apply the change is made. If this second attempt fails, 1127 ** the original row is restored to the database before continuing. 1128 ** 1129 ** <dt>SQLITE_CHANGESET_ABORT<dd> 1130 ** If this value is returned, any changes applied so far are rolled back 1131 ** and the call to sqlite3changeset_apply() returns SQLITE_ABORT. 1132 ** </dl> 1133 */ 1134 #define SQLITE_CHANGESET_OMIT 0 1135 #define SQLITE_CHANGESET_REPLACE 1 1136 #define SQLITE_CHANGESET_ABORT 2 1137 1138 /* 1139 ** CAPI3REF: Streaming Versions of API functions. 1140 ** 1141 ** The six streaming API xxx_strm() functions serve similar purposes to the 1142 ** corresponding non-streaming API functions: 1143 ** 1144 ** <table border=1 style="margin-left:8ex;margin-right:8ex"> 1145 ** <tr><th>Streaming function<th>Non-streaming equivalent</th> 1146 ** <tr><td>sqlite3changeset_apply_str<td>[sqlite3changeset_apply] 1147 ** <tr><td>sqlite3changeset_concat_str<td>[sqlite3changeset_concat] 1148 ** <tr><td>sqlite3changeset_invert_str<td>[sqlite3changeset_invert] 1149 ** <tr><td>sqlite3changeset_start_str<td>[sqlite3changeset_start] 1150 ** <tr><td>sqlite3session_changeset_str<td>[sqlite3session_changeset] 1151 ** <tr><td>sqlite3session_patchset_str<td>[sqlite3session_patchset] 1152 ** </table> 1153 ** 1154 ** Non-streaming functions that accept changesets (or patchsets) as input 1155 ** require that the entire changeset be stored in a single buffer in memory. 1156 ** Similarly, those that return a changeset or patchset do so by returning 1157 ** a pointer to a single large buffer allocated using sqlite3_malloc(). 1158 ** Normally this is convenient. However, if an application running in a 1159 ** low-memory environment is required to handle very large changesets, the 1160 ** large contiguous memory allocations required can become onerous. 1161 ** 1162 ** In order to avoid this problem, instead of a single large buffer, input 1163 ** is passed to a streaming API functions by way of a callback function that 1164 ** the sessions module invokes to incrementally request input data as it is 1165 ** required. In all cases, a pair of API function parameters such as 1166 ** 1167 ** <pre> 1168 ** int nChangeset, 1169 ** void *pChangeset, 1170 ** </pre> 1171 ** 1172 ** Is replaced by: 1173 ** 1174 ** <pre> 1175 ** int (*xInput)(void *pIn, void *pData, int *pnData), 1176 ** void *pIn, 1177 ** </pre> 1178 ** 1179 ** Each time the xInput callback is invoked by the sessions module, the first 1180 ** argument passed is a copy of the supplied pIn context pointer. The second 1181 ** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no 1182 ** error occurs the xInput method should copy up to (*pnData) bytes of data 1183 ** into the buffer and set (*pnData) to the actual number of bytes copied 1184 ** before returning SQLITE_OK. If the input is completely exhausted, (*pnData) 1185 ** should be set to zero to indicate this. Or, if an error occurs, an SQLite 1186 ** error code should be returned. In all cases, if an xInput callback returns 1187 ** an error, all processing is abandoned and the streaming API function 1188 ** returns a copy of the error code to the caller. 1189 ** 1190 ** In the case of sqlite3changeset_start_strm(), the xInput callback may be 1191 ** invoked by the sessions module at any point during the lifetime of the 1192 ** iterator. If such an xInput callback returns an error, the iterator enters 1193 ** an error state, whereby all subsequent calls to iterator functions 1194 ** immediately fail with the same error code as returned by xInput. 1195 ** 1196 ** Similarly, streaming API functions that return changesets (or patchsets) 1197 ** return them in chunks by way of a callback function instead of via a 1198 ** pointer to a single large buffer. In this case, a pair of parameters such 1199 ** as: 1200 ** 1201 ** <pre> 1202 ** int *pnChangeset, 1203 ** void **ppChangeset, 1204 ** </pre> 1205 ** 1206 ** Is replaced by: 1207 ** 1208 ** <pre> 1209 ** int (*xOutput)(void *pOut, const void *pData, int nData), 1210 ** void *pOut 1211 ** </pre> 1212 ** 1213 ** The xOutput callback is invoked zero or more times to return data to 1214 ** the application. The first parameter passed to each call is a copy of the 1215 ** pOut pointer supplied by the application. The second parameter, pData, 1216 ** points to a buffer nData bytes in size containing the chunk of output 1217 ** data being returned. If the xOutput callback successfully processes the 1218 ** supplied data, it should return SQLITE_OK to indicate success. Otherwise, 1219 ** it should return some other SQLite error code. In this case processing 1220 ** is immediately abandoned and the streaming API function returns a copy 1221 ** of the xOutput error code to the application. 1222 ** 1223 ** The sessions module never invokes an xOutput callback with the third 1224 ** parameter set to a value less than or equal to zero. Other than this, 1225 ** no guarantees are made as to the size of the chunks of data returned. 1226 */ 1227 int sqlite3changeset_apply_strm( 1228 sqlite3 *db, /* Apply change to "main" db of this handle */ 1229 int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */ 1230 void *pIn, /* First arg for xInput */ 1231 int(*xFilter)( 1232 void *pCtx, /* Copy of sixth arg to _apply() */ 1233 const char *zTab /* Table name */ 1234 ), 1235 int(*xConflict)( 1236 void *pCtx, /* Copy of sixth arg to _apply() */ 1237 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */ 1238 sqlite3_changeset_iter *p /* Handle describing change and conflict */ 1239 ), 1240 void *pCtx /* First argument passed to xConflict */ 1241 ); 1242 int sqlite3changeset_concat_strm( 1243 int (*xInputA)(void *pIn, void *pData, int *pnData), 1244 void *pInA, 1245 int (*xInputB)(void *pIn, void *pData, int *pnData), 1246 void *pInB, 1247 int (*xOutput)(void *pOut, const void *pData, int nData), 1248 void *pOut 1249 ); 1250 int sqlite3changeset_invert_strm( 1251 int (*xInput)(void *pIn, void *pData, int *pnData), 1252 void *pIn, 1253 int (*xOutput)(void *pOut, const void *pData, int nData), 1254 void *pOut 1255 ); 1256 int sqlite3changeset_start_strm( 1257 sqlite3_changeset_iter **pp, 1258 int (*xInput)(void *pIn, void *pData, int *pnData), 1259 void *pIn 1260 ); 1261 int sqlite3session_changeset_strm( 1262 sqlite3_session *pSession, 1263 int (*xOutput)(void *pOut, const void *pData, int nData), 1264 void *pOut 1265 ); 1266 int sqlite3session_patchset_strm( 1267 sqlite3_session *pSession, 1268 int (*xOutput)(void *pOut, const void *pData, int nData), 1269 void *pOut 1270 ); 1271 int sqlite3changegroup_add_strm(sqlite3_changegroup*, 1272 int (*xInput)(void *pIn, void *pData, int *pnData), 1273 void *pIn 1274 ); 1275 int sqlite3changegroup_output_strm(sqlite3_changegroup*, 1276 int (*xOutput)(void *pOut, const void *pData, int nData), 1277 void *pOut 1278 ); 1279 1280 1281 /* 1282 ** Make sure we can call this stuff from C++. 1283 */ 1284 #ifdef __cplusplus 1285 } 1286 #endif 1287 1288 #endif /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */ 1289