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PHP与MYSQL交互函数表学习笔记

2024-07-24 12:57:01
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最近一直在研究php与mysql,感觉php与mysql交互的函数都是过程化的,当然也有mysqli扩展,面向对象,java和c#写多了之后,再写php,有些不适应,感觉又回到了学c的年代。今天学习了一些函数,记录下来,以便日后忘记时,可以参考。

说 明 函 数 说 明
建立数据库连接mysql_connect()resource mysql_connect([string hostname [:port] [:/path/to/socket] [, string username] [, string password]])
示例:$conn = @mysql_connect("localhost", "username", "password") or dir("不能连接到mysql server");
使用该连接必须显示的关闭连接
建立数据库连接mysql_pconnect()resource mysql_pconnect([string hostname [:port] [:/path/to/socket] [, string username] [, string password]])
示例:$conn = @mysql_pconnect("localhost", "username", "password") or dir("不能连接到mysql server");
使用该连接函数不需要显示的关闭连接,它相当于使用了连接池
关闭数据库连接mysql_close()$conn = @mysql_connect("localhost", "username", "password") or die("不能连接到mysql server");
@mysql_select_db("mydatabase") or die("
不能选择这个数据库,或数据库不存在");
echo "
你已经连接到mydatabase数据库
";
mysql_close();
 
选择数据库mysql_select_db()boolean mysql_select_db(string db_name [, resource link_id])
$conn = @mysql_connect("localhost", "username", "password") or die("
不能连接到mysql server");
@mysql_select_db("mydatabase") or die("
不能选择这个数据库,或数据库不存在");
 
查询mysqlmysql_query()resource mysql_query (string query, [resource link_id])
$linkid = @mysql_connect("localhost", "username", "password") or die("
不能连接到mysql server");
@mysql_select_db("mydatabase") or die("
不能选择这个数据库,或者数据库不存在");
$query = "select * from mytable";
$result = mysql_query($query);
mysql_close();
sql查询执行成功,则返回资源标识符,失败时返回false。若执行更新成功,则返回true,否则返回false
查询mysqlmysql_db_query()resource mysql_db_query(string database, string query [, resource link_id])
$linkid = @mysql_connect("localhost", "username", "password") or die("
不能连接到mysqlserver");
$query = "select * from mytable";
$result = mysql_db_query("mydatabase", $query);
mysql_close();
为了使代码清晰,不推荐使用这个函数调用
获取和显示数据mysql_result()mixed mysql_result (resource result_set, int row [, mixed field])
$query = "select id, name from mytable order by name";
$result = mysql_query($query);
$c_id = mysql_result($result, 0, "id");
$c_name = mysql_result($result, 0, "name");
最简单、也是效率最低的数据获取函数
获取和显示数据mysql_fetch_row()array mysql_fetch_row (resource result_set)
$query = "select id, name from mytable order by name";
$result = mysql_query($query);
while (list($id, $name) = mysql_fetch_row($result)) {
        echo("name: $name ($id) <br />");
}
函数从result_set中获取整个数据行,将值放在一个索引数组中。通常会结使list()函数使用
获取和显示数据mysql_fetch_array()array mysql_fetch_array (resource result_set [, int result_type])
$query = "select id, name from mytable order by name";
$result = mysql_query($query);
while($row = mysql_fetch_array($result, mysql_assoc)) {
        $id = $row["id"];
        $name = $row["name"];
        echo "name: $name ($id) <br />";
}
result_type的值有:
mysql_assoc:
字段名表示键,字段内容为值
mysql_num: 数值索引数组,操作与mysql_fetch_ros()
函数一样
mysql_both: 即作为关联数组又作为数值索引数组返回。result_type的默认值。
获取和显示数据mysql_fetch_assoc()array mysql_fetch_assoc (resource result_set)
相当于调用 mysql_fetch_array(resource, mysql_assoc);
 
获取和显示数据mysql_fetch_object()object mysql_fetch_object(resource result_set)
$query = "select id, name from mytable order by name";
while ($row = mysql_fetch_object($result)) {
        $id = $row->id;
        $name = $row->name;
        echo "name: $name ($id) <br />";
}
在操作上与mysql_fetch_array()相同
所选择的记录mysql_num_rows()int mysql_num_rows(resource result_set)
#query = "select id, name from mytable where id > 65";
$result = mysql_query($query);
echo "
".mysql_num_rows($result)."条记录的id大于65";
只在确定select查询所获取的记录数时才有用。
受影响的记录mysql_affected_rows()int mysql_affected_rows([resource link_id])
$query = "update mytable set name='cheneyfu' where id>=5";
$result = mysql_query($query);
echo "id
大于等于5的名称被更新了的记录数:".mysql_affected_rows();
该函数获取受insert,updatedelete更新语句影响的行数
获取数据库列表信息mysql_list_dbs()resource mysql_list_dbs([resource link_id])
mysql_connect("localhost", "username", "password");
$dbs = mysql_list_dbs();
echo "databases: <br />";
while (list($db) = mysql_fetch_rows($dbs)) {
        echo "$db <br />";
}
 
获取数据库名mysql_db_name()string mysql_db_name(resource result_set, integer index)该函数获取在mysql_list_dbs()所返回result_set中位于指定index索引的数据库名
获取数据库表列表mysql_list_tables()resource mysql_list_tables(string database [, resource link_id])
mysql_connect("localhost", "username", "password");
$tables = mysql_list_tables("mydatabase");
while (list($table) = mysql_fetch_row($tables)) {
        echo "$table <br />";
}
该函数获取database中所有表的表名
获取数据库表名mysql_tablename()string mysql_tablename(resource result_set, integer index)
mysql_connect("localhost", "username", "password");
$tables = mysql_list_tables("mydatabase");
$count = -1;
while (++$count < mysql_numrows($tables)) {
        echo mysql_tablename($tables, $count)."<br />";
}
该函数获取mysql_list_tables()所返回result_set中位于指定index索引的表名
获取字段信息mysql_fetch_field()object mysql_fetch_field(resource result [, int field_offset])
mysql_connect("localhost", "username", "password");
mysql_select_db("mydatabase");
$query = "select * from mytable";
$result = mysql_query($query);
$fields = mysql_num_fields($result);
for($count = 0; $count < $fieds; $count++) {
       $field = mysql_fetch_field($result, $count);
       echo "<p>$field->name  $field->type  ($field->max_length) </p>";
}
返回的对象共有12个对象属性:
name:
字段名
table:
字段所在的表
max_length:
字段的最大长度
not_null: 如果字段不能为null,则为1,否则
0
primary_key:
如果字段为主键,则为1,否则
0
unique_key:
如果字段是唯一键,则为1 否则
0
multiple_key:
如果字段为非唯一,则为1,否则
0
numeric:
如果字段为数值则为1,否则
0
blob:
如果字段为blob则为1,否则为
0
type:
字段的数据类型
unsigned: 如果字段为无符号数则为1,否则为
0
zerofill:
如果字段为“零填充”则为1 否则为0
获取查询的字段数mysql_num_fields()integer mysql_num_fields (resource result_set)
$query = "select id, name from mytable order by name";
$result = mysql_query($query);
echo "
这个查询的字段数是:".mysql_num_fields($result)."<br />";
返回查询result_set中的字段数
获取指定表的所有字段的字段名mysql_list_fields()resource mysql_list_fields (string database_name, string table_name [, resource link_id])
$fields = mysql_list_fields("mydatabase", "mytable");
echo "
数据库mydatabase中表mytable的字段数: ".mysql_num_fields($fields)."<br />";
 
获取指定的字段选项mysql_field_flags()string mysql_field_flags (resource result_set, integer field_offset) 
获取指定的字段的最大长度mysql_field_len()integer mysql_field_len (resource result_set, integer field_offset)
$query = "select name from mytable";
$result = mysql_query($query);
$row = mysql_fetch_row($result);
echo mysql_field_len($result, 0)."<br />";
如果mysql_field_len($reseult, 0) = 16777215
那么numer_format(mysql_field_len($result))等于16,777,215
获取字段名mysql_field_name()string mysql_field_name (resource result_set, int field_offset)
$query = "select id as pkid, name from mytable order by name";
$result = mysql_query($query);
$row = mysql_fetch_row($result);
echo mysql_field_name($result, 0); // result: pkid
 
获取字段类型mysql_field_type()string mysql_field_type (resource result_set, int field_offset)
$query = "select id, name from mytable order by name";
$result = mysql_query($query);
$row = mysql_fetch_row($result);
echo mysql_field_type($result, 0); // result: int
 
获取字段所在表名mysql_field_table()string mysql_field_table (resource result_set, int field_offset)
$query = "select id as pkid, name from mytable order by name";
$result = mysql_query($query);
$row = mysql_fetch_row($result);
echo mysql_field_table($result, 0);  //

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