PHP 操作MYSQL基础知识

2. mysql_connect()
3. resource mysql_connect([string hostname [:port] [:/path/to/socket] [, string username] [, string password]])
4. 示例：$conn = @mysql_connect("localhost", "username", "password") or dir("不能连接到Mysql Server");
5. 使用该连接必须显示的关闭连接

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建立数据库连接

2. mysql_pconnect()
3. resource mysql_pconnect([string hostname [:port] [:/path/to/socket] [, string username] [, string password]])
4. 示例：$conn = @mysql_pconnect("localhost", "username", "password") or dir("不能连接到Mysql Server");
5. 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

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关闭数据库连接

2. mysql_close()
3. $conn = @mysql_connect("localhost", "username", "password") or die("不能连接到Mysql Server");
4. @mysql_select_db("MyDatabase") or die("不能选择这个数据库，或数据库不存在");
5. echo "你已经连接到MyDatabase数据库";
6. mysql_close();

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选择数据库

2. mysql_select_db()
3. boolean mysql_select_db(string db_name [, resource link_id])
4. $conn = @mysql_connect("localhost", "username", "password") or die("不能连接到Mysql Server");
5. @mysql_select_db("MyDatabase") or die("不能选择这个数据库，或数据库不存在");

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查询MySQL

2. mysql_query()
3. resource mysql_query (string query, [resource link_id])
4. $linkId = @mysql_connect("localhost", "username", "password") or die("不能连接到Mysql Server");
5. @mysql_select_db("MyDatabase") or die("不能选择这个数据库，或者数据库不存在");
6. $query = "select * from MyTable";
7. $result = mysql_query($query);
8. mysql_close();
9. 若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

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查询MySQL

2. mysql_db_query()
3. resource mysql_db_query(string database, string query [, resource link_id])
4. $linkId = @mysql_connect("localhost", "username", "password") or die("不能连接到MysqlServer");
5. $query = "select * from MyTable";
6. $result = mysql_db_query("MyDatabase", $query);
7. mysql_close();
8. 为了使代码清晰，不推荐使用这个函数调用

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获取和显示数据

2. mysql_result()
3. mixed mysql_result (resource result_set, int row [, mixed field])
4. $query = "select id, name from MyTable order by name";
5. $result = mysql_query($query);
6. $c_id = mysql_result($result, 0, "id");
7. $c_name = mysql_result($result, 0, "name");
8. 最简单、也是效率最低的数据获取函数

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获取和显示数据

2. mysql_fetch_row()
3. array mysql_fetch_row (resource result_set)
4. $query = "select id, name from MyTable order by name";
5. $result = mysql_query($query);
6. while (list($id, $name) = mysql_fetch_row($result)) {
7. echo("Name: $name ($id)
   ");
8. }
9. 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

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获取和显示数据

2. mysql_fetch_array()
3. array mysql_fetch_array (resource result_set [, int result_type])
4. $query = "select id, name from MyTable order by name";
5. $result = mysql_query($query);
6. while($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
7. $id = $row["id"];
8. $name = $row["name"];
9. echo "Name: $name ($id)
   ";
10. }
11. result_type的值有：
12. MYSQL_ASSOC: 字段名表示键，字段内容为值
13. MYSQL_NUM: 数值索引数组，操作与mysql_fetch_ros()函数一样
14. 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。

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获取和显示数据

2. mysql_fetch_assoc()
3. array mysql_fetch_assoc (resource result_set)
4. 相当于调用 mysql_fetch_array(resource, MYSQL_ASSOC);

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获取和显示数据

2. mysql_fetch_object()
3. object mysql_fetch_object(resource result_set)
4. $query = "select id, name from MyTable order by name";
5. while ($row = mysql_fetch_object($result)) {
6. $id = $row->id;
7. $name = $row->name;
8. echo "Name: $name ($id)
   ";
9. }
10. 在操作上与mysql_fetch_array()相同

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所选择的记录

2. mysql_num_rows()
3. int mysql_num_rows(resource result_set)
4. #query = "select id, name from MyTable where id > 65";
5. $result = mysql_query($query);
6. echo "有".mysql_num_rows($result)."条记录的ID大于65";
7. 只在确定select查询所获取的记录数时才有用。

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受影响的记录

2. mysql_affected_rows()
3. int mysql_affected_rows([resource link_id])
4. $query = "update MyTable set name="CheneyFu" where id>=5";
5. $result = mysql_query($query);
6. echo "ID大于等于5的名称被更新了的记录数：".mysql_affected_rows();
7. 该函数获取受INSERT,UPDATE或DELETE更新语句影响的行数

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获取数据库列表信息

2. mysql_list_dbs()
3. resource mysql_list_dbs([resource link_id])
4. mysql_connect("localhost", "username", "password");
5. $dbs = mysql_list_dbs();
6. echo "Databases:
   ";
7. while (list($db) = mysql_fetch_rows($dbs)) {
8. echo "$db
   ";
9. }

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获取数据库名

2. mysql_db_name()
3. string mysql_db_name(resource result_set, integer index)
4. 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

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获取数据库表列表

2. mysql_list_tables()
3. resource mysql_list_tables(string database [, resource link_id])
4. mysql_connect("localhost", "username", "password");
5. $tables = mysql_list_tables("MyDatabase");
6. while (list($table) = mysql_fetch_row($tables)) {
7. echo "$table
   ";
8. }该函数获取database中所有表的表名

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获取数据库表名

2. mysql_tablename()
3. string mysql_tablename(resource result_set, integer index)
4. mysql_connect("localhost", "username", "password");
5. $tables = mysql_list_tables("MyDatabase");
6. $count = -1;
7. while (++$count echo mysql_tablename($tables, $count)."
   ";
8. }
9. 该函数获取mysql_list_tables()所返回result_set中位于指定index索引的表名

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获取字段信息

2. mysql_fetch_field()
3. object mysql_fetch_field(resource result [, int field_offset])
4. mysql_connect("localhost", "username", "password");
5. mysql_select_db("MyDatabase");
6. $query = "select * from MyTable";
7. $result = mysql_query($query);
8. $fields = mysql_num_fields($result);
9. for($count = 0; $count $field = mysql_fetch_field($result, $count);
10. echo "

    $field->name $field->type ($field->max_length)

    ";
11. }

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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

2. mysql_num_fields()
3. integer mysql_num_fields (resource result_set)
4. $query = "select id, name from MyTable order by name";
5. $result = mysql_query($query);
6. echo "这个查询的字段数是：".mysql_num_fields($result)."
   ";

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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

2. mysql_list_fields()
3. resource mysql_list_fields (string database_name, string table_name [, resource link_id])
4. $fields = mysql_list_fields("MyDatabase", "MyTable");
5. echo "数据库MyDatabase中表MyTable的字段数： ".mysql_num_fields($fields)."
   ";

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获取指定的字段选项

2. mysql_field_flags()
3. string mysql_field_flags (resource result_set, integer field_offset)

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获取指定的字段的最大长度

2. mysql_field_len()
3. integer mysql_field_len (resource result_set, integer field_offset)
4. $query = "select name from MyTable";
5. $result = mysql_query($query);
6. $row = mysql_fetch_row($result);
7. echo mysql_field_len($result, 0)."
   ";
8. 如果mysql_field_len($reseult, 0) = 16777215
9. 那么numer_format(mysql_field_len($result))等于16,777,215

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获取字段名

2. mysql_field_name()
3. string mysql_field_name (resource result_set, int field_offset)
4. $query = "select id as PKID, name from MyTable order by name";
5. $result = mysql_query($query);
6. $row = mysql_fetch_row($result);
7. echo mysql_field_name($result, 0); // Result: PKID

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获取字段类型

2. mysql_field_type()
3. string mysql_field_type (resource result_set, int field_offset)
4. $query = "select id, name from MyTable order by name";
5. $result = mysql_query($query);
6. $row = mysql_fetch_row($result);
7. echo mysql_field_type($result, 0); // Result: int

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获取字段所在表名

2. mysql_field_table()
3. string mysql_field_table (resource result_set, int field_offset)
4. $query = "select id as PKID, name from MyTable order by name";
5. $result = mysql_query($query);
6. $row = mysql_fetch_row($result);
7. echo mysql_field_table($result, 0); // Result: MyTable

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