Function getColDefaultValueFromNil

pkg/table/column.go:668–707

(ctx expression.BuildContext, col *model.ColumnInfo, args *getColOriginDefaultValue)

}

func getColDefaultValueFromNil(ctx expression.BuildContext, col *model.ColumnInfo, args *getColOriginDefaultValue) (types.Datum, error) {
	if !mysql.HasNotNullFlag(col.GetFlag()) {
		return types.Datum{}, nil
	}
	if col.GetType() == 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
		defEnum, err := types.ParseEnumValue(col.FieldType.GetElems(), 1)
		if err != nil {
			return types.Datum{}, err
		}
		return types.NewCollateMysqlEnumDatum(defEnum, col.GetCollate()), nil
	}
	if mysql.HasAutoIncrementFlag(col.GetFlag()) {
		// Auto increment column doesn't have default value and we should not return error.
		return GetZeroValue(col), nil
	}
	evalCtx := ctx.GetEvalCtx()
	var strictSQLMode bool
	if args != nil {
		strictSQLMode = args.StrictSQLMode
	} else {
		strictSQLMode = evalCtx.SQLMode().HasStrictMode()
	}
	if !strictSQLMode {
		evalCtx.AppendWarning(ErrNoDefaultValue.FastGenByArgs(col.Name))
		return GetZeroValue(col), nil
	}
	ec := evalCtx.ErrCtx()
	var err error
	if mysql.HasNoDefaultValueFlag(col.GetFlag()) {
		err = ErrNoDefaultValue.FastGenByArgs(col.Name)
	} else {
		err = ErrColumnCantNull.FastGenByArgs(col.Name)
	}
	if ec.HandleError(err) == nil {
		return GetZeroValue(col), nil
	}
	return types.Datum{}, ErrNoDefaultValue.GenWithStackByArgs(col.Name)
}

// GetZeroValue gets zero value for given column type.
func GetZeroValue(col *model.ColumnInfo) types.Datum {