Implement the RowsColumnTypeScanType interface in the go sql driver

go/vt/vitessdriver/rows.go

@@ -17,10 +17,14 @@ limitations under the License.
 package vitessdriver
 
 import (
+	"database/sql"
 	"database/sql/driver"
 	"io"
+	"reflect"
+	"time"
 
 	"vitess.io/vitess/go/sqltypes"
+	"vitess.io/vitess/go/vt/proto/query"
 )
 
 // rows creates a database/sql/driver compliant Row iterator
@@ -58,3 +62,60 @@ func (ri *rows) Next(dest []driver.Value) error {
 	ri.index++
 	return nil
 }
+
+var (
+	typeInt8     = reflect.TypeOf(int8(0))
+	typeUint8    = reflect.TypeOf(uint8(0))
+	typeInt16    = reflect.TypeOf(int16(0))
+	typeUint16   = reflect.TypeOf(uint16(0))
+	typeInt32    = reflect.TypeOf(int32(0))
+	typeUint32   = reflect.TypeOf(uint32(0))
+	typeInt64    = reflect.TypeOf(int64(0))
+	typeUint64   = reflect.TypeOf(uint64(0))
+	typeFloat32  = reflect.TypeOf(float32(0))
+	typeFloat64  = reflect.TypeOf(float64(0))
+	typeRawBytes = reflect.TypeOf(sql.RawBytes{})
+	typeTime     = reflect.TypeOf(time.Time{})
+	typeUnknown  = reflect.TypeOf(new(interface{}))
+)
+
+// Implements the RowsColumnTypeScanType interface
+func (ri *rows) ColumnTypeScanType(index int) reflect.Type {
+	field := ri.qr.Fields[index]
+	switch field.GetType() {
+	case query.Type_INT8:
+		return typeInt8
+	case query.Type_UINT8:
+		return typeUint8
+	case query.Type_INT16, query.Type_YEAR:
+		return typeInt16
+	case query.Type_UINT16:
+		return typeUint16
+	case query.Type_INT24:
+		return typeInt32
+	case query.Type_UINT24: // no 24 bit type, using 32 instead
+		return typeUint32
+	case query.Type_INT32:
+		return typeInt32
+	case query.Type_UINT32:
+		return typeUint32
+	case query.Type_INT64:
+		return typeInt64
+	case query.Type_UINT64:
+		return typeUint64
+	case query.Type_FLOAT32:
+		return typeFloat32
+	case query.Type_FLOAT64:
+		return typeFloat64
+	case query.Type_TIMESTAMP, query.Type_DECIMAL, query.Type_VARCHAR, query.Type_TEXT,
+		query.Type_BLOB, query.Type_VARBINARY, query.Type_CHAR, query.Type_BINARY, query.Type_BIT,
+		query.Type_ENUM, query.Type_SET, query.Type_TUPLE, query.Type_GEOMETRY, query.Type_JSON,
+		query.Type_HEXNUM, query.Type_HEXVAL, query.Type_BITNUM:
+
+		return typeRawBytes
+	case query.Type_DATE, query.Type_TIME, query.Type_DATETIME:
+		return typeTime
+	default:
+		return typeUnknown
+	}
+}

go/vt/vitessdriver/rows_test.go

@@ -18,10 +18,12 @@ package vitessdriver
 
 import (
 	"database/sql/driver"
+	"fmt"
 	"io"
 	"reflect"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"vitess.io/vitess/go/sqltypes"
@@ -135,3 +137,92 @@ func TestRows(t *testing.T) {
 
 	_ = ri.Close()
 }
+
+// Test that the ColumnTypeScanType function returns the correct reflection type for each
+// sql type. The sql type in turn comes from a table column's type.
+func TestColumnTypeScanType(t *testing.T) {
+	var r = sqltypes.Result{
+		Fields: []*querypb.Field{
+			{
+				Name: "field1",
+				Type: sqltypes.Int8,
+			},
+			{
+				Name: "field2",
+				Type: sqltypes.Uint8,
+			},
+			{
+				Name: "field3",
+				Type: sqltypes.Int16,
+			},
+			{
+				Name: "field4",
+				Type: sqltypes.Uint16,
+			},
+			{
+				Name: "field5",
+				Type: sqltypes.Int24,
+			},
+			{
+				Name: "field6",
+				Type: sqltypes.Uint24,
+			},
+			{
+				Name: "field7",
+				Type: sqltypes.Int32,
+			},
+			{
+				Name: "field8",
+				Type: sqltypes.Uint32,
+			},
+			{
+				Name: "field9",
+				Type: sqltypes.Int64,
+			},
+			{
+				Name: "field10",
+				Type: sqltypes.Uint64,
+			},
+			{
+				Name: "field11",
+				Type: sqltypes.Float32,
+			},
+			{
+				Name: "field12",
+				Type: sqltypes.Float64,
+			},
+			{
+				Name: "field13",
+				Type: sqltypes.VarBinary,
+			},
+			{
+				Name: "field14",
+				Type: sqltypes.Datetime,
+			},
+		},
+	}
+
+	ri := newRows(&r, &converter{}).(driver.RowsColumnTypeScanType)
+	defer ri.Close()
+
+	wantTypes := []reflect.Type{
+		typeInt8,
+		typeUint8,
+		typeInt16,
+		typeUint16,
+		typeInt32,
+		typeUint32,
+		typeInt32,
+		typeUint32,
+		typeInt64,
+		typeUint64,
+		typeFloat32,
+		typeFloat64,
+		typeRawBytes,
+		typeTime,
+	}
+
+	for i := 0; i < len(wantTypes); i++ {
+		assert.Equal(t, ri.ColumnTypeScanType(i), wantTypes[i], fmt.Sprintf("unexpected type %v, wanted %v", ri.ColumnTypeScanType(i), wantTypes[i]))
+	}
+}