tcl/sql/pltcl_trigger.sql

-- suppress CONTEXT so that function OIDs aren't in output
\set VERBOSITY terse

--
-- Create the tables used in the test queries
--
-- T_pkey1 is the primary key table for T_dta1. Entries from T_pkey1
-- Cannot be changed or deleted if they are referenced from T_dta1.
--
-- T_pkey2 is the primary key table for T_dta2. If the key values in
-- T_pkey2 are changed, the references in T_dta2 follow. If entries
-- are deleted, the referencing entries from T_dta2 are deleted too.
-- The values for field key2 in T_pkey2 are silently converted to
-- upper case on insert/update.
--
create table T_pkey1 (
    key1	int4,
    key2	char(20),
    txt		char(40)
);

create table T_pkey2 (
    key1	int4,
    key2	char(20),
    txt		char(40)
);

create table T_dta1 (
    tkey	char(10),
    ref1	int4,
    ref2	char(20)
);

create table T_dta2 (
    tkey	char(10),
    ref1	int4,
    ref2	char(20)
);


--
-- Function to check key existence in T_pkey1
--
create function check_pkey1_exists(int4, bpchar) returns bool as E'
    if {![info exists GD]} {
        set GD(plan) [spi_prepare				\\
	    "select 1 from T_pkey1				\\
	        where key1 = \\$1 and key2 = \\$2"		\\
	    {int4 bpchar}]
    }

    set n [spi_execp -count 1 $GD(plan) [list $1 $2]]

    if {$n > 0} {
        return "t"
    }
    return "f"
' language pltcl;


-- dump trigger data

CREATE TABLE trigger_test (
	i int,
	v text,
	dropme text,
	test_skip boolean DEFAULT false,
	test_return_null boolean DEFAULT false,
	test_argisnull boolean DEFAULT false
);
-- Make certain dropped attributes are handled correctly
ALTER TABLE trigger_test DROP dropme;

CREATE TABLE trigger_test_generated (
   i int,
   j int GENERATED ALWAYS AS (i * 2) STORED
);

CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;

CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
	if {$TG_table_name eq "trigger_test" && $TG_level eq "ROW" && $TG_op ne "DELETE"} {
		# Special case tests
		if {$NEW(test_return_null) eq "t" } {
			return_null
		}
		if {$NEW(test_argisnull) eq "t" } {
			set should_error [argisnull 1]
		}
		if {$NEW(test_skip) eq "t" } {
			elog NOTICE "SKIPPING OPERATION $TG_op"
			return SKIP
		}
	}

	if { [info exists TG_relid] } {
	set TG_relid "bogus:12345"
	}

	set dnames [info locals {[a-zA-Z]*} ]

	foreach key [lsort $dnames] {

		if { [array exists $key] } {
			set str "{"
			foreach akey [lsort [ array names $key ] ] {
				if {[string length $str] > 1} { set str "$str, " }
				set cmd "($akey)"
				set cmd "set val \$$key$cmd"
				eval $cmd
				set str "$str$akey: $val"
			}
			set str "$str}"
		elog NOTICE "$key: $str"
		} else {
			set val [eval list "\$$key" ]
		elog NOTICE "$key: $val"
		}
	}


	return OK

$_$;

CREATE TRIGGER show_trigger_data_trig
BEFORE INSERT OR UPDATE OR DELETE ON trigger_test
FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
CREATE TRIGGER statement_trigger
BEFORE INSERT OR UPDATE OR DELETE OR TRUNCATE ON trigger_test
FOR EACH STATEMENT EXECUTE PROCEDURE trigger_data(42,'statement trigger');

CREATE TRIGGER show_trigger_data_trig_before
BEFORE INSERT OR UPDATE OR DELETE ON trigger_test_generated
FOR EACH ROW EXECUTE PROCEDURE trigger_data();
CREATE TRIGGER show_trigger_data_trig_after
AFTER INSERT OR UPDATE OR DELETE ON trigger_test_generated
FOR EACH ROW EXECUTE PROCEDURE trigger_data();

CREATE TRIGGER show_trigger_data_view_trig
INSTEAD OF INSERT OR UPDATE OR DELETE ON trigger_test_view
FOR EACH ROW EXECUTE PROCEDURE trigger_data(24,'skidoo view');

--
-- Trigger function on every change to T_pkey1
--
create function trig_pkey1_before() returns trigger as E'
    #
    # Create prepared plans on the first call
    #
    if {![info exists GD]} {
	#
	# Plan to check for duplicate key in T_pkey1
	#
        set GD(plan_pkey1) [spi_prepare				\\
	    "select check_pkey1_exists(\\$1, \\$2) as ret"	\\
	    {int4 bpchar}]
	#
	# Plan to check for references from T_dta1
	#
        set GD(plan_dta1) [spi_prepare				\\
	    "select 1 from T_dta1				\\
	        where ref1 = \\$1 and ref2 = \\$2"		\\
	    {int4 bpchar}]
    }

    #
    # Initialize flags
    #
    set check_old_ref 0
    set check_new_dup 0

    switch $TG_op {
        INSERT {
	    #
	    # Must check for duplicate key on INSERT
	    #
	    set check_new_dup 1
	}
	UPDATE {
	    #
	    # Must check for duplicate key on UPDATE only if
	    # the key changes. In that case we must check for
	    # references to OLD values too.
	    #
	    if {[string compare $NEW(key1) $OLD(key1)] != 0} {
	        set check_old_ref 1
		set check_new_dup 1
	    }
	    if {[string compare $NEW(key2) $OLD(key2)] != 0} {
	        set check_old_ref 1
		set check_new_dup 1
	    }
	}
	DELETE {
	    #
	    # Must only check for references to OLD on DELETE
	    #
	    set check_old_ref 1
	}
    }

    if {$check_new_dup} {
	#
	# Check for duplicate key
	#
        spi_execp -count 1 $GD(plan_pkey1) [list $NEW(key1) $NEW(key2)]
	if {$ret == "t"} {
	    elog ERROR \\
	        "duplicate key ''$NEW(key1)'', ''$NEW(key2)'' for T_pkey1"
	}
    }

    if {$check_old_ref} {
	#
	# Check for references to OLD
	#
        set n [spi_execp -count 1 $GD(plan_dta1) [list $OLD(key1) $OLD(key2)]]
	if {$n > 0} {
	    elog ERROR \\
	        "key ''$OLD(key1)'', ''$OLD(key2)'' referenced by T_dta1"
	}
    }

    #
    # Anything is fine - let operation pass through
    #
    return OK
' language pltcl;


create trigger pkey1_before before insert or update or delete on T_pkey1
	for each row execute procedure
	trig_pkey1_before();


--
-- Trigger function to check for duplicate keys in T_pkey2
-- and to force key2 to be upper case only without leading whitespaces
--
create function trig_pkey2_before() returns trigger as E'
    #
    # Prepare plan on first call
    #
    if {![info exists GD]} {
        set GD(plan_pkey2) [spi_prepare				\\
	    "select 1 from T_pkey2				\\
	        where key1 = \\$1 and key2 = \\$2"		\\
	    {int4 bpchar}]
    }

    #
    # Convert key2 value
    #
    set NEW(key2) [string toupper [string trim $NEW(key2)]]

    #
    # Check for duplicate key
    #
    set n [spi_execp -count 1 $GD(plan_pkey2) [list $NEW(key1) $NEW(key2)]]
    if {$n > 0} {
	elog ERROR \\
	    "duplicate key ''$NEW(key1)'', ''$NEW(key2)'' for T_pkey2"
    }

    #
    # Return modified tuple in NEW
    #
    return [array get NEW]
' language pltcl;


create trigger pkey2_before before insert or update on T_pkey2
	for each row execute procedure
	trig_pkey2_before();


--
-- Trigger function to force references from T_dta2 follow changes
-- in T_pkey2 or be deleted too. This must be done AFTER the changes
-- in T_pkey2 are done so the trigger for primkey check on T_dta2
-- fired on our updates will see the new key values in T_pkey2.
--
create function trig_pkey2_after() returns trigger as E'
    #
    # Prepare plans on first call
    #
    if {![info exists GD]} {
	#
	# Plan to update references from T_dta2
	#
        set GD(plan_dta2_upd) [spi_prepare			\\
	    "update T_dta2 set ref1 = \\$3, ref2 = \\$4		\\
	        where ref1 = \\$1 and ref2 = \\$2"		\\
	    {int4 bpchar int4 bpchar}]
	#
	# Plan to delete references from T_dta2
	#
        set GD(plan_dta2_del) [spi_prepare			\\
	    "delete from T_dta2 				\\
	        where ref1 = \\$1 and ref2 = \\$2"		\\
	    {int4 bpchar}]
    }

    #
    # Initialize flags
    #
    set old_ref_follow 0
    set old_ref_delete 0

    switch $TG_op {
	UPDATE {
	    #
	    # On update we must let old references follow
	    #
	    set NEW(key2) [string toupper $NEW(key2)]

	    if {[string compare $NEW(key1) $OLD(key1)] != 0} {
	        set old_ref_follow 1
	    }
	    if {[string compare $NEW(key2) $OLD(key2)] != 0} {
	        set old_ref_follow 1
	    }
	}
	DELETE {
	    #
	    # On delete we must delete references too
	    #
	    set old_ref_delete 1
	}
    }

    if {$old_ref_follow} {
	#
	# Let old references follow and fire NOTICE message if
	# there where some
	#
        set n [spi_execp $GD(plan_dta2_upd) \\
	    [list $OLD(key1) $OLD(key2) $NEW(key1) $NEW(key2)]]
	if {$n > 0} {
	    elog NOTICE \\
		"updated $n entries in T_dta2 for new key in T_pkey2"
        }
    }

    if {$old_ref_delete} {
	#
	# delete references and fire NOTICE message if
	# there where some
	#
        set n [spi_execp $GD(plan_dta2_del) \\
	    [list $OLD(key1) $OLD(key2)]]
	if {$n > 0} {
	    elog NOTICE \\
		"deleted $n entries from T_dta2"
        }
    }

    return OK
' language pltcl;


create trigger pkey2_after after update or delete on T_pkey2
	for each row execute procedure
	trig_pkey2_after();


--
-- Generic trigger function to check references in T_dta1 and T_dta2
--
create function check_primkey() returns trigger as E'
    #
    # For every trigger/relation pair we create
    # a saved plan and hold them in GD
    #
    set plankey [list "plan" $TG_name $TG_relid]
    set planrel [list "relname" $TG_relid]

    #
    # Extract the pkey relation name
    #
    set keyidx [expr [llength $args] / 2]
    set keyrel [string tolower [lindex $args $keyidx]]

    if {![info exists GD($plankey)]} {
	#
	# We must prepare a new plan. Build up a query string
	# for the primary key check.
	#
	set keylist [lrange $args [expr $keyidx + 1] end]

        set query "select 1 from $keyrel"
	set qual " where"
	set typlist ""
	set idx 1
	foreach key $keylist {
	    set key [string tolower $key]
	    #
	    # Add the qual part to the query string
	    #
	    append query "$qual $key = \\$$idx"
	    set qual " and"

	    #
	    # Lookup the fields type in pg_attribute
	    #
	    set n [spi_exec "select T.typname			\\
	        from pg_catalog.pg_type T, pg_catalog.pg_attribute A, pg_catalog.pg_class C	\\
		where C.relname  = ''[quote $keyrel]''		\\
		  and C.oid      = A.attrelid			\\
		  and A.attname  = ''[quote $key]''		\\
		  and A.atttypid = T.oid"]
	    if {$n != 1} {
	        elog ERROR "table $keyrel doesn''t have a field named $key"
	    }

	    #
	    # Append the fields type to the argument type list
	    #
	    lappend typlist $typname
	    incr idx
	}

	#
	# Prepare the plan
	#
	set GD($plankey) [spi_prepare $query $typlist]

	#
	# Lookup and remember the table name for later error messages
	#
	spi_exec "select relname from pg_catalog.pg_class	\\
		where oid = ''$TG_relid''::oid"
	set GD($planrel) $relname
    }

    #
    # Build the argument list from the NEW row
    #
    incr keyidx -1
    set arglist ""
    foreach arg [lrange $args 0 $keyidx] {
        lappend arglist $NEW($arg)
    }

    #
    # Check for the primary key
    #
    set n [spi_execp -count 1 $GD($plankey) $arglist]
    if {$n <= 0} {
        elog ERROR "key for $GD($planrel) not in $keyrel"
    }

    #
    # Anything is fine
    #
    return OK
' language pltcl;


create trigger dta1_before before insert or update on T_dta1
	for each row execute procedure
	check_primkey('ref1', 'ref2', 'T_pkey1', 'key1', 'key2');


create trigger dta2_before before insert or update on T_dta2
	for each row execute procedure
	check_primkey('ref1', 'ref2', 'T_pkey2', 'key1', 'key2');


insert into T_pkey1 values (1, 'key1-1', 'test key');
insert into T_pkey1 values (1, 'key1-2', 'test key');
insert into T_pkey1 values (1, 'key1-3', 'test key');
insert into T_pkey1 values (2, 'key2-1', 'test key');
insert into T_pkey1 values (2, 'key2-2', 'test key');
insert into T_pkey1 values (2, 'key2-3', 'test key');

insert into T_pkey2 values (1, 'key1-1', 'test key');
insert into T_pkey2 values (1, 'key1-2', 'test key');
insert into T_pkey2 values (1, 'key1-3', 'test key');
insert into T_pkey2 values (2, 'key2-1', 'test key');
insert into T_pkey2 values (2, 'key2-2', 'test key');
insert into T_pkey2 values (2, 'key2-3', 'test key');

select * from T_pkey1;

-- key2 in T_pkey2 should have upper case only
select * from T_pkey2;

insert into T_pkey1 values (1, 'KEY1-3', 'should work');

-- Due to the upper case translation in trigger this must fail
insert into T_pkey2 values (1, 'KEY1-3', 'should fail');

insert into T_dta1 values ('trec 1', 1, 'key1-1');
insert into T_dta1 values ('trec 2', 1, 'key1-2');
insert into T_dta1 values ('trec 3', 1, 'key1-3');

-- Must fail due to unknown key in T_pkey1
insert into T_dta1 values ('trec 4', 1, 'key1-4');

insert into T_dta2 values ('trec 1', 1, 'KEY1-1');
insert into T_dta2 values ('trec 2', 1, 'KEY1-2');
insert into T_dta2 values ('trec 3', 1, 'KEY1-3');

-- Must fail due to unknown key in T_pkey2
insert into T_dta2 values ('trec 4', 1, 'KEY1-4');

select * from T_dta1;

select * from T_dta2;

update T_pkey1 set key2 = 'key2-9' where key1 = 2 and key2 = 'key2-1';
update T_pkey1 set key2 = 'key1-9' where key1 = 1 and key2 = 'key1-1';
delete from T_pkey1 where key1 = 2 and key2 = 'key2-2';
delete from T_pkey1 where key1 = 1 and key2 = 'key1-2';

update T_pkey2 set key2 = 'KEY2-9' where key1 = 2 and key2 = 'KEY2-1';
update T_pkey2 set key2 = 'KEY1-9' where key1 = 1 and key2 = 'KEY1-1';
delete from T_pkey2 where key1 = 2 and key2 = 'KEY2-2';
delete from T_pkey2 where key1 = 1 and key2 = 'KEY1-2';

select * from T_pkey1;
select * from T_pkey2;
select * from T_dta1;
select * from T_dta2;

select tcl_avg(key1) from T_pkey1;
select tcl_sum(key1) from T_pkey1;
select tcl_avg(key1) from T_pkey2;
select tcl_sum(key1) from T_pkey2;

-- The following should return NULL instead of 0
select tcl_avg(key1) from T_pkey1 where key1 = 99;
select tcl_sum(key1) from T_pkey1 where key1 = 99;

select 1 @< 2;
select 100 @< 4;

select * from T_pkey1 order by key1 using @<, key2 collate "C";
select * from T_pkey2 order by key1 using @<, key2 collate "C";

-- show dump of trigger data
insert into trigger_test values(1,'insert');

insert into trigger_test_generated (i) values (1);
update trigger_test_generated set i = 11 where i = 1;
delete from trigger_test_generated;

insert into trigger_test_view values(2,'insert');
update trigger_test_view set v = 'update' where i=1;
delete from trigger_test_view;

update trigger_test set v = 'update', test_skip=true where i = 1;
update trigger_test set v = 'update' where i = 1;
delete from trigger_test;
truncate trigger_test;

DROP TRIGGER show_trigger_data_trig_before ON trigger_test_generated;
DROP TRIGGER show_trigger_data_trig_after ON trigger_test_generated;

-- should error
insert into trigger_test(test_argisnull) values(true);

-- should error
insert into trigger_test(test_return_null) values(true);

-- test transition table visibility
create table transition_table_test (id int, name text);
insert into transition_table_test values (1, 'a');
create function transition_table_test_f() returns trigger language pltcl as
$$
  spi_exec -array C "SELECT id, name FROM old_table" {
    elog INFO "old: $C(id) -> $C(name)"
  }
  spi_exec -array C "SELECT id, name FROM new_table" {
    elog INFO "new: $C(id) -> $C(name)"
  }
  return OK
$$;
CREATE TRIGGER a_t AFTER UPDATE ON transition_table_test
  REFERENCING OLD TABLE AS old_table NEW TABLE AS new_table
  FOR EACH STATEMENT EXECUTE PROCEDURE transition_table_test_f();
update transition_table_test set name = 'b';
drop table transition_table_test;
drop function transition_table_test_f();

-- dealing with generated columns

CREATE FUNCTION generated_test_func1() RETURNS trigger
LANGUAGE pltcl
AS $$
# not allowed
set NEW(j) 5
return [array get NEW]
$$;

CREATE TRIGGER generated_test_trigger1 BEFORE INSERT ON trigger_test_generated
FOR EACH ROW EXECUTE PROCEDURE generated_test_func1();

TRUNCATE trigger_test_generated;
INSERT INTO trigger_test_generated (i) VALUES (1);
SELECT * FROM trigger_test_generated;