Golang mysql.HasNoDefaultValueFlag函数代码示例

// GetColDefaultValue gets default value of the column.
func GetColDefaultValue(ctx context.Context, col *model.ColumnInfo) (interface{}, bool, error) {
	// Check no default value flag.
	if mysql.HasNoDefaultValueFlag(col.Flag) && col.Tp != mysql.TypeEnum {
		return nil, false, errors.Errorf("Field '%s' doesn't have a default value", col.Name)
	}

	// Check and get timestamp/datetime default value.
	if col.Tp == mysql.TypeTimestamp || col.Tp == mysql.TypeDatetime {
		if col.DefaultValue == nil {
			return nil, true, nil
		}

		value, err := expression.GetTimeValue(ctx, col.DefaultValue, col.Tp, col.Decimal)
		if err != nil {
			return nil, true, errors.Errorf("Field '%s' get default value fail - %s", col.Name, errors.Trace(err))
		}

		return value, true, nil
	} else if col.Tp == mysql.TypeEnum {
		// For enum type, if no default value and not null is set,
		// the default value is the first element of the enum list
		if col.DefaultValue == nil && mysql.HasNotNullFlag(col.Flag) {
			return col.FieldType.Elems[0], true, nil
		}
	}

	return col.DefaultValue, true, nil
}

// getColDefaultValue gets default value of the column.
func getColDefaultValue(col *model.ColumnInfo) (interface{}, bool, error) {
	// Check no default value flag.
	if mysql.HasNoDefaultValueFlag(col.Flag) && col.Tp != mysql.TypeEnum {
		return nil, false, errors.Errorf("Field '%s' doesn't have a default value", col.Name)
	}

	// Check and get timestamp/datetime default value.
	if col.Tp == mysql.TypeEnum {
		// For enum type, if no default value and not null is set,
		// the default value is the first element of the enum list
		if col.DefaultValue == nil && mysql.HasNotNullFlag(col.Flag) {
			return col.FieldType.Elems[0], true, nil
		}
	}

	return col.DefaultValue, true, nil
}

// NewColDesc returns a new ColDesc for a column.
func NewColDesc(col *Column) *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:      "",
	}
}

// GetColDefaultValue gets default value of the column.
func GetColDefaultValue(ctx context.Context, col *model.ColumnInfo) (types.Datum, bool, error) {
	// Check no default value flag.
	if mysql.HasNoDefaultValueFlag(col.Flag) && col.Tp != mysql.TypeEnum {
		err := errNoDefaultValue.Gen("Field '%s' doesn't have a default value", col.Name)
		if ctx != nil {
			sessVars := variable.GetSessionVars(ctx)
			if !sessVars.StrictSQLMode {
				// TODO: add warning.
				return GetZeroValue(col), true, nil
			}
		}
		return types.Datum{}, false, errors.Trace(err)
	}

	// Check and get timestamp/datetime default value.
	if col.Tp == mysql.TypeTimestamp || col.Tp == mysql.TypeDatetime {
		if col.DefaultValue == nil {
			return types.Datum{}, true, nil
		}

		value, err := evaluator.GetTimeValue(ctx, col.DefaultValue, col.Tp, col.Decimal)
		if err != nil {
			return types.Datum{}, true, errGetDefaultFailed.Gen("Field '%s' get default value fail - %s",
				col.Name, errors.Trace(err))
		}
		return value, true, nil
	} else if col.Tp == mysql.TypeEnum {
		// For enum type, if no default value and not null is set,
		// the default value is the first element of the enum list
		if col.DefaultValue == nil && mysql.HasNotNullFlag(col.Flag) {
			return types.NewDatum(col.FieldType.Elems[0]), true, nil
		}
	}
	value, err := CastValue(ctx, types.NewDatum(col.DefaultValue), col)
	if err != nil {
		return types.Datum{}, false, errors.Trace(err)
	}
	return value, true, nil
}

func (e *ShowExec) fetchShowCreateTable() error {
	tb, err := e.getTable()
	if err != nil {
		return errors.Trace(err)
	}

	// TODO: let the result more like MySQL.
	var buf bytes.Buffer
	buf.WriteString(fmt.Sprintf("CREATE TABLE `%s` (\n", tb.Meta().Name.O))
	var pkCol *table.Column
	for i, col := range tb.Cols() {
		buf.WriteString(fmt.Sprintf("  `%s` %s", col.Name.O, col.GetTypeDesc()))
		if mysql.HasAutoIncrementFlag(col.Flag) {
			buf.WriteString(" NOT NULL AUTO_INCREMENT")
		} else {
			if mysql.HasNotNullFlag(col.Flag) {
				buf.WriteString(" NOT NULL")
			}
			if !mysql.HasNoDefaultValueFlag(col.Flag) {
				switch col.DefaultValue {
				case nil:
					buf.WriteString(" DEFAULT NULL")
				case "CURRENT_TIMESTAMP":
					buf.WriteString(" DEFAULT CURRENT_TIMESTAMP")
				default:
					buf.WriteString(fmt.Sprintf(" DEFAULT '%v'", col.DefaultValue))
				}
			}
			if mysql.HasOnUpdateNowFlag(col.Flag) {
				buf.WriteString(" ON UPDATE CURRENT_TIMESTAMP")
			}
		}
		if len(col.Comment) > 0 {
			buf.WriteString(fmt.Sprintf(" COMMENT '%s'", col.Comment))
		}
		if i != len(tb.Cols())-1 {
			buf.WriteString(",\n")
		}
		if tb.Meta().PKIsHandle && mysql.HasPriKeyFlag(col.Flag) {
			pkCol = col
		}
	}

	if pkCol != nil {
		// If PKIsHanle, pk info is not in tb.Indices(). We should handle it here.
		buf.WriteString(",\n")
		buf.WriteString(fmt.Sprintf(" PRIMARY KEY (`%s`)", pkCol.Name.O))
	}

	if len(tb.Indices()) > 0 || len(tb.Meta().ForeignKeys) > 0 {
		buf.WriteString(",\n")
	}

	for i, idx := range tb.Indices() {
		idxInfo := idx.Meta()
		if idxInfo.Primary {
			buf.WriteString("  PRIMARY KEY ")
		} else if idxInfo.Unique {
			buf.WriteString(fmt.Sprintf("  UNIQUE KEY `%s` ", idxInfo.Name.O))
		} else {
			buf.WriteString(fmt.Sprintf("  KEY `%s` ", idxInfo.Name.O))
		}

		cols := make([]string, 0, len(idxInfo.Columns))
		for _, c := range idxInfo.Columns {
			cols = append(cols, c.Name.O)
		}
		buf.WriteString(fmt.Sprintf("(`%s`)", strings.Join(cols, "`,`")))
		if i != len(tb.Indices())-1 {
			buf.WriteString(",\n")
		}
	}

	if len(tb.Indices()) > 0 && len(tb.Meta().ForeignKeys) > 0 {
		buf.WriteString(",\n")
	}

	for _, fk := range tb.Meta().ForeignKeys {
		if fk.State != model.StatePublic {
			continue
		}

		cols := make([]string, 0, len(fk.Cols))
		for _, c := range fk.Cols {
			cols = append(cols, c.O)
		}

		refCols := make([]string, 0, len(fk.RefCols))
		for _, c := range fk.Cols {
			refCols = append(refCols, c.O)
		}

		buf.WriteString(fmt.Sprintf("  CONSTRAINT `%s` FOREIGN KEY (`%s`)", fk.Name.O, strings.Join(cols, "`,`")))
		buf.WriteString(fmt.Sprintf(" REFERENCES `%s` (`%s`)", fk.RefTable.O, strings.Join(refCols, "`,`")))

		if ast.ReferOptionType(fk.OnDelete) != ast.ReferOptionNoOption {
			buf.WriteString(fmt.Sprintf(" ON DELETE %s", ast.ReferOptionType(fk.OnDelete)))
		}

		if ast.ReferOptionType(fk.OnUpdate) != ast.ReferOptionNoOption {
//.........这里部分代码省略.........