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- /*
- Copyright 2017 Google LLC
-
- Licensed under the Apache License, Version 2.0 (the "License");
- you may not use this file except in compliance with the License.
- You may obtain a copy of the License at
-
- http://www.apache.org/licenses/LICENSE-2.0
-
- Unless required by applicable law or agreed to in writing, software
- distributed under the License is distributed on an "AS IS" BASIS,
- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- See the License for the specific language governing permissions and
- limitations under the License.
- */
-
- package spanner
-
- import (
- "errors"
- "fmt"
-
- proto3 "github.com/golang/protobuf/ptypes/struct"
-
- sppb "google.golang.org/genproto/googleapis/spanner/v1"
- "google.golang.org/grpc/codes"
- )
-
- // A Statement is a SQL query with named parameters.
- //
- // A parameter placeholder consists of '@' followed by the parameter name.
- // Parameter names consist of any combination of letters, numbers, and
- // underscores. Names may be entirely numeric (e.g., "WHERE m.id = @5").
- // Parameters may appear anywhere that a literal value is expected. The same
- // parameter name may be used more than once. It is an error to execute a
- // statement with unbound parameters. On the other hand, it is allowable to
- // bind parameter names that are not used.
- //
- // See the documentation of the Row type for how Go types are mapped to Cloud
- // Spanner types.
- type Statement struct {
- SQL string
- Params map[string]interface{}
- }
-
- // NewStatement returns a Statement with the given SQL and an empty Params map.
- func NewStatement(sql string) Statement {
- return Statement{SQL: sql, Params: map[string]interface{}{}}
- }
-
- // errBindParam returns error for not being able to bind parameter to query request.
- func errBindParam(k string, v interface{}, err error) error {
- if err == nil {
- return nil
- }
- se, ok := toSpannerError(err).(*Error)
- if !ok {
- return spannerErrorf(codes.InvalidArgument, "failed to bind query parameter(name: %q, value: %v), error = <%v>", k, v, err)
- }
- se.decorate(fmt.Sprintf("failed to bind query parameter(name: %q, value: %v)", k, v))
- return se
- }
-
- var (
- errNilParam = errors.New("use T(nil), not nil")
- errNoType = errors.New("no type information")
- )
-
- // bindParams binds parameters in a Statement to a sppb.ExecuteSqlRequest or sppb.PartitionQueryRequest.
- func (s *Statement) bindParams(i interface{}) error {
- params := &proto3.Struct{
- Fields: map[string]*proto3.Value{},
- }
- paramTypes := map[string]*sppb.Type{}
- for k, v := range s.Params {
- if v == nil {
- return errBindParam(k, v, errNilParam)
- }
- val, t, err := encodeValue(v)
- if err != nil {
- return errBindParam(k, v, err)
- }
- if t == nil { // should not happen, because of nil check above
- return errBindParam(k, v, errNoType)
- }
- params.Fields[k] = val
- paramTypes[k] = t
- }
-
- switch r := i.(type) {
- default:
- return fmt.Errorf("failed to bind query parameter, unexpected request type: %v", r)
- case *sppb.ExecuteSqlRequest:
- r.Params = params
- r.ParamTypes = paramTypes
- case *sppb.PartitionQueryRequest:
- r.Params = params
- r.ParamTypes = paramTypes
- }
- return nil
- }
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