Oracle、MysqL、sqlServer创建表和给表和字段加注释 
一、Oracle
--创建表
create table test ( 
     id varchar2(200) primary key not null,sort number,name varchar(200)
)
--字段加注释
comment on column test.id is ‘id‘; 
comment on column test.sort is ‘序号‘;
--表加注释
comment on table test is ‘测试表‘ 

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 二.MysqL
--创建表
create table test ( 
     id varchar(200) not null,sort int(11) comment ‘排序‘,name varchar(200) comment  ‘名称‘,)           
--表加注释
alter table test comment =‘测试表‘ 

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三.sqlServer
--创建表
create table test ( 
     id varchar(200) primary key not null,sort int,name varchar(200),)
--给字段加注释
EXEC sp_addextendedproperty N‘test‘,N‘序号‘,N‘user‘,N‘dbo‘,N‘table‘,N‘test‘,N‘column‘,N‘sort‘;
--表加注释
EXECUTE sp_addextendedproperty N‘test‘,N‘测试表‘,NULL,NULL 
删除字段注释  
execute sp_dropextendedproperty ‘MS_Description‘,‘user‘,‘dbo‘,‘table‘,‘testTable‘,‘column‘,‘testRecord‘;  
删除表注释  
execute sp_dropextendedproperty ‘MS_Description‘,null,null;   

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sqlserver

--表加注释
EXECUTE sp_addextendedproperty N‘MS_Description‘,N‘账号类型表‘,N‘Account_Type‘,NULL 
--获取表注释
SELECT isnull(B.name,‘‘)as name,A.value FROM sys.extended_properties A
LEFT JOIN sys.columns B ON A.major_id=B.object_id AND A.minor_id=B.column_id
LEFT JOIN sys.tables C ON A.major_id=C.object_id
WHERE A.class=1 AND C.name=‘Account_Type‘ and isnull(B.name,‘‘)=‘‘

--给字段加注释
EXEC sp_addextendedproperty N‘MS_Description‘,N‘Type_Id‘;
--获取字段注释
SELECT A.value FROM sys.extended_properties A
LEFT JOIN sys.columns B ON A.major_id=B.object_id AND A.minor_id=B.column_id
LEFT JOIN sys.tables C ON A.major_id=C.object_id
WHERE A.class=1 AND B.name=‘Type_Id‘ AND C.name=‘Account_Type‘