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gitea/vendor/github.com/pingcap/tidb/column/column.go

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// Copyright 2013 The ql Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSES/QL-LICENSE file.
// Copyright 2015 PingCAP, Inc.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package column
import (
"strings"
"github.com/juju/errors"
"github.com/pingcap/tidb/context"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/model"
"github.com/pingcap/tidb/mysql"
"github.com/pingcap/tidb/util/types"
)
// Col provides meta data describing a table column.
type Col struct {
model.ColumnInfo
}
// PrimaryKeyName defines primary key name.
const PrimaryKeyName = "PRIMARY"
// IndexedCol defines an index with info.
type IndexedCol struct {
model.IndexInfo
X kv.Index
}
// String implements fmt.Stringer interface.
func (c *Col) String() string {
ans := []string{c.Name.O, types.TypeToStr(c.Tp, c.Charset)}
if mysql.HasAutoIncrementFlag(c.Flag) {
ans = append(ans, "AUTO_INCREMENT")
}
if mysql.HasNotNullFlag(c.Flag) {
ans = append(ans, "NOT NULL")
}
return strings.Join(ans, " ")
}
// FindCol finds column in cols by name.
func FindCol(cols []*Col, name string) *Col {
for _, col := range cols {
if strings.EqualFold(col.Name.O, name) {
return col
}
}
return nil
}
// FindCols finds columns in cols by names.
func FindCols(cols []*Col, names []string) ([]*Col, error) {
var rcols []*Col
for _, name := range names {
col := FindCol(cols, name)
if col != nil {
rcols = append(rcols, col)
} else {
return nil, errors.Errorf("unknown column %s", name)
}
}
return rcols, nil
}
// FindOnUpdateCols finds columns which have OnUpdateNow flag.
func FindOnUpdateCols(cols []*Col) []*Col {
var rcols []*Col
for _, col := range cols {
if mysql.HasOnUpdateNowFlag(col.Flag) {
rcols = append(rcols, col)
}
}
return rcols
}
// CastValues casts values based on columns type.
func CastValues(ctx context.Context, rec []types.Datum, cols []*Col) (err error) {
for _, c := range cols {
var converted types.Datum
converted, err = rec[c.Offset].ConvertTo(&c.FieldType)
if err != nil {
return errors.Trace(err)
}
rec[c.Offset] = converted
}
return nil
}
// ColDesc describes column information like MySQL desc and show columns do.
type ColDesc struct {
Field string
Type string
Collation string
Null string
Key string
DefaultValue interface{}
Extra string
Privileges string
Comment string
}
const defaultPrivileges string = "select,insert,update,references"
// GetTypeDesc gets the description for column type.
func (c *Col) GetTypeDesc() string {
desc := c.FieldType.CompactStr()
if mysql.HasUnsignedFlag(c.Flag) {
desc += " UNSIGNED"
}
return desc
}
// NewColDesc returns a new ColDesc for a column.
func NewColDesc(col *Col) *ColDesc {
// TODO: if we have no primary key and a unique index which's columns are all not null
// we will set these columns' flag as PriKeyFlag
// see https://dev.mysql.com/doc/refman/5.7/en/show-columns.html
// create table
name := col.Name
nullFlag := "YES"
if mysql.HasNotNullFlag(col.Flag) {
nullFlag = "NO"
}
keyFlag := ""
if mysql.HasPriKeyFlag(col.Flag) {
keyFlag = "PRI"
} else if mysql.HasUniKeyFlag(col.Flag) {
keyFlag = "UNI"
} else if mysql.HasMultipleKeyFlag(col.Flag) {
keyFlag = "MUL"
}
var defaultValue interface{}
if !mysql.HasNoDefaultValueFlag(col.Flag) {
defaultValue = col.DefaultValue
}
extra := ""
if mysql.HasAutoIncrementFlag(col.Flag) {
extra = "auto_increment"
} else if mysql.HasOnUpdateNowFlag(col.Flag) {
extra = "on update CURRENT_TIMESTAMP"
}
return &ColDesc{
Field: name.O,
Type: col.GetTypeDesc(),
Collation: col.Collate,
Null: nullFlag,
Key: keyFlag,
DefaultValue: defaultValue,
Extra: extra,
Privileges: defaultPrivileges,
Comment: "",
}
}
// ColDescFieldNames returns the fields name in result set for desc and show columns.
func ColDescFieldNames(full bool) []string {
if full {
return []string{"Field", "Type", "Collation", "Null", "Key", "Default", "Extra", "Privileges", "Comment"}
}
return []string{"Field", "Type", "Null", "Key", "Default", "Extra"}
}
// CheckOnce checks if there are duplicated column names in cols.
func CheckOnce(cols []*Col) error {
m := map[string]struct{}{}
for _, col := range cols {
name := col.Name
_, ok := m[name.L]
if ok {
return errors.Errorf("column specified twice - %s", name)
}
m[name.L] = struct{}{}
}
return nil
}
// CheckNotNull checks if nil value set to a column with NotNull flag is set.
func (c *Col) CheckNotNull(data types.Datum) error {
if mysql.HasNotNullFlag(c.Flag) && data.Kind() == types.KindNull {
return errors.Errorf("Column %s can't be null.", c.Name)
}
return nil
}
// IsPKHandleColumn checks if the column is primary key handle column.
func (c *Col) IsPKHandleColumn(tbInfo *model.TableInfo) bool {
return mysql.HasPriKeyFlag(c.Flag) && tbInfo.PKIsHandle
}
// CheckNotNull checks if row has nil value set to a column with NotNull flag set.
func CheckNotNull(cols []*Col, row []types.Datum) error {
for _, c := range cols {
if err := c.CheckNotNull(row[c.Offset]); err != nil {
return errors.Trace(err)
}
}
return nil
}
// FetchValues fetches indexed values from a row.
func (idx *IndexedCol) FetchValues(r []types.Datum) ([]types.Datum, error) {
vals := make([]types.Datum, len(idx.Columns))
for i, ic := range idx.Columns {
if ic.Offset < 0 || ic.Offset > len(r) {
return nil, errors.New("Index column offset out of bound")
}
vals[i] = r[ic.Offset]
}
return vals, nil
}