1/* 2Copyright 2017 Google LLC 3 4Licensed under the Apache License, Version 2.0 (the "License"); 5you may not use this file except in compliance with the License. 6You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10Unless required by applicable law or agreed to in writing, software 11distributed under the License is distributed on an "AS IS" BASIS, 12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13See the License for the specific language governing permissions and 14limitations under the License. 15*/ 16 17package spanner 18 19import ( 20 "errors" 21 "fmt" 22 23 proto3 "github.com/golang/protobuf/ptypes/struct" 24 structpb "github.com/golang/protobuf/ptypes/struct" 25 sppb "google.golang.org/genproto/googleapis/spanner/v1" 26 "google.golang.org/grpc/codes" 27) 28 29// A Statement is a SQL query with named parameters. 30// 31// A parameter placeholder consists of '@' followed by the parameter name. 32// The parameter name is an identifier which must conform to the naming 33// requirements in https://cloud.google.com/spanner/docs/lexical#identifiers. 34// Parameters may appear anywhere that a literal value is expected. The same 35// parameter name may be used more than once. It is an error to execute a 36// statement with unbound parameters. On the other hand, it is allowable to 37// bind parameter names that are not used. 38// 39// See the documentation of the Row type for how Go types are mapped to Cloud 40// Spanner types. 41type Statement struct { 42 SQL string 43 Params map[string]interface{} 44} 45 46// NewStatement returns a Statement with the given SQL and an empty Params map. 47func NewStatement(sql string) Statement { 48 return Statement{SQL: sql, Params: map[string]interface{}{}} 49} 50 51var ( 52 errNilParam = errors.New("use T(nil), not nil") 53 errNoType = errors.New("no type information") 54) 55 56// convertParams converts a statement's parameters into proto Param and 57// ParamTypes. 58func (s *Statement) convertParams() (*structpb.Struct, map[string]*sppb.Type, error) { 59 params := &proto3.Struct{ 60 Fields: map[string]*proto3.Value{}, 61 } 62 paramTypes := map[string]*sppb.Type{} 63 for k, v := range s.Params { 64 if v == nil { 65 return nil, nil, errBindParam(k, v, errNilParam) 66 } 67 val, t, err := encodeValue(v) 68 if err != nil { 69 return nil, nil, errBindParam(k, v, err) 70 } 71 if t == nil { // should not happen, because of nil check above 72 return nil, nil, errBindParam(k, v, errNoType) 73 } 74 params.Fields[k] = val 75 paramTypes[k] = t 76 } 77 78 return params, paramTypes, nil 79} 80 81// errBindParam returns error for not being able to bind parameter to query 82// request. 83func errBindParam(k string, v interface{}, err error) error { 84 if err == nil { 85 return nil 86 } 87 var se *Error 88 if !errorAs(err, &se) { 89 return spannerErrorf(codes.InvalidArgument, "failed to bind query parameter(name: %q, value: %v), error = <%v>", k, v, err) 90 } 91 se.decorate(fmt.Sprintf("failed to bind query parameter(name: %q, value: %v)", k, v)) 92 return se 93} 94