# maxdb_stmt_prepare

# maxdb_stmt::prepare

(PECL maxdb >= 1.0)

maxdb_stmt_prepare -- maxdb_stmt::prepare — Prepare an SQL statement for execution

### 说明

过程化风格

maxdb_stmt_prepare ( resource `$stmt` , string `$query` ) : bool

面向对象风格

maxdb_stmt::prepare ( string `$query` ) : mixed

maxdb_stmt_prepare() prepares the SQL query pointed to by the null-terminated string query. The statement resource has to be allocated by maxdb_stmt_init(). The query must consist of a single SQL statement.

> Note:

> You should not add a terminating semicolon or \g to the statement.

The parameter `query` can include one or more parameter markers in the SQL statement by embedding question mark (?) characters at the appropriate positions.

> Note:

> The markers are legal only in certain places in SQL statements. For example, they are allowed in the VALUES() list of an INSERT statement (to specify column values for a row), or in a comparison with a column in a WHERE clause to specify a comparison value.

> However, they are not allowed for identifiers (such as table or column names), in the select list that names the columns to be returned by a SELECT statement), or to specify both operands of a binary operator such as the = equal sign. The latter restriction is necessary because it would be impossible to determine the parameter type. In general, parameters are legal only in Data Manipulation Languange (DML) statements, and not in Data Defination Language (DDL) statements.

The parameter markers must be bound to application variables using maxdb_stmt_bind_param() and/or maxdb_stmt_bind_result() before executing the statement or fetching rows.

### 返回值

成功时返回 `TRUE`， 或者在失败时返回 `FALSE`。

### 范例

Example #1 面向对象风格

    <?php
    $maxdb = new maxdb("localhost", "MONA", "RED", "DEMODB");

    /* check connection */
    if (maxdb_connect_errno()) {
       printf("Connect failed: %s\n", maxdb_connect_error());
       exit();
    }

    $city = "Portland";

    /* create a prepared statement */
    $stmt =  $maxdb->stmt_init();
    if ($stmt->prepare("SELECT state FROM hotel.city WHERE name=?")) {

       /* bind parameters for markers */
       $stmt->bind_param("s", $city);

       /* execute query */
       $stmt->execute();

       /* bind result variables */
       $stmt->bind_result($district);

       /* fetch value */
       $stmt->fetch();

       printf("%s is in district %s\n", $city, $district);

       /* close statement */
       $stmt->close();
    }

    /* close connection */
    $maxdb->close();
    ?>

Example #2 过程化风格

    <?php
    $link = maxdb_connect("localhost", "MONA", "RED", "DEMODB");

    /* check connection */
    if (maxdb_connect_errno()) {
       printf("Connect failed: %s\n", maxdb_connect_error());
       exit();
    }

    $city = "Portland";

    /* create a prepared statement */
    $stmt = maxdb_stmt_init($link);
    if (maxdb_stmt_prepare($stmt, "SELECT state FROM hotel.city WHERE name=?")) {

       /* bind parameters for markers */
       maxdb_stmt_bind_param($stmt, "s", $city);

       /* execute query */
       maxdb_stmt_execute($stmt);

       /* bind result variables */
       maxdb_stmt_bind_result($stmt, $district);

       /* fetch value */
       maxdb_stmt_fetch($stmt);

       printf("%s is in district %s\n", $city, $district);

       /* close statement */
       maxdb_stmt_close($stmt);
    }

    /* close connection */
    maxdb_close($link);
    ?>

以上例程的输出类似于：

    Portland is in district OR

### 参见

- maxdb_stmt_init() - Initializes a statement and returns an resource for use with maxdb_stmt_prepare
- maxdb_stmt_execute() - Executes a prepared Query
- maxdb_stmt_fetch() - Fetch results from a prepared statement into the bound variables
- maxdb_stmt_bind_param() - Binds variables to a prepared statement as parameters
- maxdb_stmt_bind_result() - Binds variables to a prepared statement for result storage
- maxdb_stmt_close() - Closes a prepared statement