mysql中备注用什么数据类型 数据库中备注

sql server 添加表注释、字段注释
--为字段添加注释 
--格式如右：execute sp_addextendedproperty 'MS_Description','字段备注信息','user','dbo','table','字段所属的表名','column','添加注释的字段名';
execute sp_addextendedproperty 'MS_Description','add by liyc. 诊断类别码','user','dbo','table','DiagRecord','column','DiagTypeCode';

--修改字段注释 
execute sp_updateextendedproperty 'MS_Description','add by liyc.','user','dbo','table','DiagRecord','column','DiagTypeCode';

--删除字段注释
execute sp_dropextendedproperty 'MS_Description','user','dbo','table','DiagRecord','column','DiagTypeCode';

-- 添加表注释
execute sp_addextendedproperty 'MS_Description','诊断记录文件','user','dbo','table','DiagRecord',null,null;

-- 修改表注释
execute sp_updateextendedproperty 'MS_Description','诊断记录文件1','user','dbo','table','DiagRecord',null,null;

-- 删除表注释
execute sp_dropextendedproperty 'MS_Description','user','dbo','table','DiagRecord',null,null;

-- 说明：
-- 1.增加、修改、删除注释调用不同的存储过程  
-- 2.增加、修改注释调用的存储过程参数数量和含义相同，删除备注比前两者少了一个“备注内容”的参数
-- 3.为表添加注释相比于为字段添加注释，最后两个参数为null

 --查看表的注释
 select isnull(value,'') from sys.extended_properties ex_p where ex_p.minor_id=0
and ex_p.major_id in (select id from sys.sysobjects a where a.name='表名')

 --查看所有表的注释
SELECT DISTINCT
	d.name,
	f.value 
FROM
	syscolumns a
	LEFT JOIN systypes b ON a.xusertype= b.xusertype
	INNER JOIN sysobjects d ON a.id= d.id 
	AND d.xtype= 'U' 
	AND d.name<> 'dtproperties'
	LEFT JOIN syscomments e ON a.cdefault= e.id
	LEFT JOIN sys.extended_properties g ON a.id= G.major_id 
	AND a.colid= g.minor_id
	LEFT JOIN sys.extended_properties f ON d.id= f.major_id 
	AND f.minor_id= 0


--查看表的所有字段注释
SELECT [ColumnName] = [Columns].name ,
        [Description] = [Properties].value,
        [SystemTypeName] = [Types].name ,
        [Precision] = [Columns].precision ,
        [Scale] = [Columns].scale ,
        [MaxLength] = [Columns].max_length ,
        [IsNullable] = [Columns].is_nullable ,
        [IsRowGUIDCol] = [Columns].is_rowguidcol ,
        [IsIdentity] = [Columns].is_identity ,
        [IsComputed] = [Columns].is_computed ,
        [IsXmlDocument] = [Columns].is_xml_document 
FROM sys.tables AS [Tables]
        INNER JOIN sys.columns AS [Columns] ON [Tables].object_id = [Columns].object_id
        INNER JOIN sys.types AS [Types] ON [Columns].system_type_id = [Types].system_type_id
                                           AND is_user_defined = 0
                                           AND [Types].name <> 'sysname'
        LEFT OUTER JOIN sys.extended_properties AS [Properties] ON [Properties].major_id = [Tables].object_id
                                                              AND [Properties].minor_id = [Columns].column_id
                                                              AND [Properties].name = 'MS_Description'
WHERE [Tables].name ='表名' -- and [Columns].name = '字段名'
ORDER BY [Columns].column_id