[英]T-SQL: Validate nvarchar ASCII characters
有没有办法知道nvarchar列的内容是否仅包含一些ASCII字符(精确地为33到127)?
You can create a validation function 您可以创建验证功能
CREATE FUNCTION [dbo].[NVarChar_Validate] (
@@Value [nvarchar](max),
@@Min [int],
@@Max [int]
)
RETURNS [bit]
AS
BEGIN
DECLARE @Index [int] SET @Index = 1
WHILE @Index <= LEN(@@Value) AND UNICODE(SUBSTRING(@@Value, @Index, 1)) BETWEEN @@Min AND @@Max
SET @Index = @Index + 1
RETURN CASE WHEN @Index > LEN(@@Value) THEN 1 ELSE 0 END
END
GO
And then add a check constraint to the table, for example: 然后将检查约束添加到表中,例如:
ALTER TABLE
[dbo].[TableToControl]
ADD CONSTRAINT
[CK_NVarChar_Validate]
CHECK (
[dbo].[NVarChar_Validate]([FieldToControl], 33, 127) = 1
)
As a result all fields will be guaranteed to have chars from 33 to 127 only. 结果,将确保所有字段的字符数只能为33至127。
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