新建表

create table [表名]

(

[自动编号字段] int IDENTITY (1,1) PRIMARY KEY ,

[字段1] nVarChar(50) default \'默认值\' null ,

[字段2] ntext null ,

[字段3] datetime,

[字段4] money null ,

[字段5] int default 0,

[字段6] Decimal (12,4) default 0,

[字段7] image null ,

)

删除表

Drop table [表名]

插入数据

INSERT INTO [表名] (字段1,字段2) VALUES (100,\'51WINDOWS.NET\')

删除数据

DELETE FROM [表名] WHERE [字段名]>100

更新数据

UPDATE [表名] SET [字段1] = 200,[字段2] = \'51WINDOWS.NET\' WHERE [字段三] = \'HAIWA\'

新增字段

ALTER TABLE [表名] ADD [字段名] NVARCHAR (50) NULL

删除字段

ALTER TABLE [表名] DROP COLUMN [字段名]

修改字段

ALTER TABLE [表名] ALTER COLUMN [字段名] NVARCHAR (50) NULL

重命名表(Access 重命名表，请参考文章：在Access数据库中重命名表)

sp_rename \'表名\', \'新表名\', \'OBJECT\'

新建约束

ALTER TABLE [表名] ADD CONSTRAINT 约束名 CHECK ([约束字段] <= \'2000-1-1\')

删除约束

ALTER TABLE [表名] DROP CONSTRAINT 约束名

新建默认值

ALTER TABLE [表名] ADD CONSTRAINT 默认值名 DEFAULT \'51WINDOWS.NET\' FOR [字段名]

删除默认值

ALTER TABLE [表名] DROP CONSTRAINT 默认值名

删除Sql Server 中的日志，减小数据库文件大小

dump transaction 数据库名 with no_log

backup log 数据库名 with no_log

dbcc shrinkdatabase(数据库名)

exec sp_dboption \'数据库名\', \'autoshrink\', \'true\'

\\\'添加字段通用函数

Sub AddColumn(TableName,ColumnName,ColumnType)

Conn.Execute(\"Alter Table \"&TableName&\" Add \"&ColumnName&\" \"&ColumnType&\"\")

End Sub

\\\'更改字段通用函数

Sub ModColumn(TableName,ColumnName,ColumnType)

Conn.Execute(\"Alter Table \"&TableName&\" Alter Column \"&ColumnName&\" \"&ColumnType&\"\")

End Sub

\\\'检查表是否存在

sql=\"select count(*) as dida from sysobjects where id = object_id(N\'[所有者].[表名]\') and OBJECTPROPERTY(id, N\'IsUserTable\') = 1\"

set rs=conn.execute(sql)

response.write rs(\"dida\")\'返回一个数值，0代表没有，1代表存在

判断表的存在

select * from sysobjects where id = object_id(N\'[dbo].[tablename]\') and OBJECTPROPERTY(id, N\'IsUserTable\') = 1

某个表的结构

select * from syscolumns where id = object_id(N\'[dbo].[你的表名]\') and OBJECTPROPERTY(id, N\'IsUserTable\') = 1

I am converting some of my code from the older mysql extension to the mysqli extension in PHP. Previously, with the mysql extension, I had used some code like this to find the primary key in a table:

while ($i < mysql_num_fields($result)) {

$meta = mysql_fetch_field($result, $i);

if ($meta->primary_key == 1){

$primary_key = $meta->name;

}

$i++;

}

$meta->primary_key == 1 was very convenient.

So far I have converted to code to using mysqli:

while ($i < $result->field_count) {

$meta = $result->fetch_field;

if ($meta->primary_key == 1){

$primary_key = $meta->name;

}

$i++;

}

Of course, from looking at the docs here we can see that $meta->primary_key doesn't exist in mysqli. I see that there is a $meta->flags. This is my best guess, although i am not sure of what value flags should be when I have a primary key.

Does anyone know how I tell which column is the primary key for a table using mysqli?

Thanks!

EDIT

Here is some working code:

//get primary key

$primary_key = '';

while ($meta = $result->fetch_field()) {

if ($meta->flags & MYSQLI_PRI_KEY_FLAG) {

$primary_key = $meta->name;

}

}

解决方案

You were very close, you will need the flags property.

The flag you are looking for is MYSQLI_PRI_KEY_FLAG, which means:

Field is part of a primary index

You can test for this flag with something like:

if ($meta->flags & MYSQLI_PRI_KEY_FLAG) {

//it is a primary key!

}

You are using & here as a Bitwise AND Operator.