MySQL操作

Posted 2020-07-26 低头捡到蛋

一、创建和连接到数据库

$con = mysql_connect("localhost", "root", "123456");
if (!$con) {
    die(‘Could not connect: ‘ . mysql_error());
}
if (mysql_query("CREATE DATABASE my_db", $con)) {
    echo "Database created";
} else {
    echo "Error creating database: " . mysql_error();
}
 @mysql_select_db(‘my_db‘,$con) or die(mysql_error());
 mysql_query("SET names UTF8");

二、删除数据库

$sql = ‘DROP DATABASE my_db‘;
$retval = mysql_query( $sql, $con );
if(! $retval )
{
  die(‘删除数据库失败: ‘ . mysql_error());
}
echo "数据库 RUNOOB 删除成功\n";

三、创建数据表

$sqler = "CREATE TABLE tableName
  (id int(10) unsigned primary key not null auto_increment,
  name varchar(32) NOT NULL default ‘0‘,
  age int(10) NOT NULL default ‘0‘, 
  content text
  )"; 
mysql_query($sqler);

四、删除数据表

$sql = "DROP TABLE tableName";
$retval = mysql_query( $sql, $con );
if(! $retval )
{
  die(‘数据表删除失败: ‘ . mysql_error());
}
echo "数据表删除成功\n";

五、增加和删除表字段

//增加字段
$sql="alter table tableName add fieldName varchar(50) not null";
$result=mysql_query($sql);


//删除字段
$sql="alter table tableName drop column fieldName";
$result=mysql_query($sql);

六、插入表数据

$name = "张三";
$age = "20";
$sex = "男";
$sql = "INSERT INTO tableName ".
       "(name,age, sex) ".
       "VALUES ".
       "(‘$name‘,‘$age‘,‘$sex‘)";
$retval = mysql_query( $sql, $con );

七、查询数据

$sql = ‘SELECT id, name, age, sex FROM tableName‘;
$retval = mysql_query( $sql, $con );
while($row = mysql_fetch_array($retval))
{
    echo "ID：{$row[‘id‘]}  <br> ".
         "Name: {$row[‘name‘]} <br> ".
         "Age: {$row[‘age‘]} <br> ".
         "Sex : {$row[‘sex‘]} <br> ".
         "--------------------------------<br>";
} 

八、修改数据

 $sql = "update tableName set name =‘{$name}‘,age=‘{$age}‘ where id=‘{$id}‘";
 $result = mysql_query($sql);

九、删除数据

$sql = "delete from tableName where id=‘{$_GET[‘id‘]}‘";
$result = mysql_query($sql);

十、关闭数据库

mysql_close($con);