找到SQL Server的数据类型为nvarchar可变长度从C#code [英] find variable length for sql server datatype nvarchar from c# code
问题描述
可以找到允许在SQL Server 2008为nvarchar的类型变量长度从C#code在asp.net应用程序?
Can I find allowed variable length for nvarchar type in sql server 2008 from c# code in asp.net application?
有关例如:
为nvarchar(?)
nvarchar(?)
我想找到的最大允许数量的?从C#code。
I want to find the maximum allowed number for "?" from c# code.
推荐答案
您可以使用此T-SQL查询来查看系统目录视图:
You can use this T-SQL query to look at the system catalog views:
SELECT
[max_length]
FROM sys.columns
WHERE [object_id] = OBJECT_ID('YourTableNameHere')
AND name = 'YourColumnNameHere'
这将返回存储定义的最大长度(以字符)的列
This will return the stored, defined maximum length (in characters) for your column
更新:如果您想找出一个键入(不是你的任何表列)的最大长度,你可以使用这个查询,而不是:
Update: if you want to find out the max length of a type (not a column of any of your tables), you can use this query instead:
SELECT
name, max_length
FROM sys.types
WHERE name IN ('varchar', 'nvarchar')
请注意:返回以字节为单位的最大长度 等你拿8000两种类型(而不是在字符!)。对于 VARCHAR
,8000字节等于8000个字符,而为nvarchar
,8000字节相当于4000个字符。
Be aware: this returns the max length in bytes (not in characters!) so you get 8000 for both types. For varchar
, 8000 bytes is equal to 8000 characters, while for nvarchar
, 8000 bytes corresponds to 4000 characters.
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