# db2_bind_param

(PECL ibm_db2 >= 1.0.0)

db2_bind_param — Binds a PHP variable to an SQL statement parameter

### 说明

db2_bind_param ( resource `$stmt` , int `$parameter_number` , string `$variable_name` [, int `$parameter_type` [, int `$data_type` = 0 [, int `$precision` = -1 [, int `$scale` = 0 ]]]] ) : bool

Binds a PHP variable to an SQL statement parameter in a statement resource returned by db2_prepare(). This function gives you more control over the parameter type, data type, precision, and scale for the parameter than simply passing the variable as part of the optional input array to db2_execute().

### 参数

`stmt`

  A prepared statement returned from db2_prepare().

`parameter_number`

  Specifies the 1-indexed position of the parameter in the prepared statement.

`variable_name`

  A string specifying the name of the PHP variable to bind to the parameter specified by `parameter_number`.

`parameter_type`

  A constant specifying whether the PHP variable should be bound to the SQL parameter as an input parameter (DB2_PARAM_IN), an output parameter (DB2_PARAM_OUT), or as a parameter that accepts input and returns output (DB2_PARAM_INOUT). To avoid memory overhead, you can also specify DB2_PARAM_FILE to bind the PHP variable to the name of a file that contains large object (BLOB, CLOB, or DBCLOB) data.

`data_type`

  A constant specifying the SQL data type that the PHP variable should be bound as: one of DB2_BINARY, DB2_CHAR, DB2_DOUBLE, or DB2_LONG .

`precision`

  Specifies the precision with which the variable should be bound to the database. This parameter can also be used for retrieving XML output values from stored procedures. A non-negative value specifies the maximum size of the XML data that will be retrieved from the database. If this parameter is not used, a default of 1MB will be assumed for retrieving the XML output value from the stored procedure.

`scale`

  Specifies the scale with which the variable should be bound to the database.

### 返回值

成功时返回 `TRUE`， 或者在失败时返回 `FALSE`。

### 范例

Example #1 Binding PHP variables to a prepared statement

The SQL statement in the following example uses two input parameters in the WHERE clause. We call db2_bind_param() to bind two PHP variables to the corresponding SQL parameters. Notice that the PHP variables do not have to be declared or assigned before the call to db2_bind_param(); in the example, $lower_limit is assigned a value before the call to db2_bind_param(), but $upper_limit is assigned a value after the call to db2_bind_param(). The variables must be bound and, for parameters that accept input, must have any value assigned, before calling db2_execute().

    <?php

    $sql = 'SELECT name, breed, weight FROM animals
        WHERE weight > ? AND weight < ?';
    $conn = db2_connect($database, $user, $password);
    $stmt = db2_prepare($conn, $sql);

    // We can declare the variable before calling db2_bind_param()
    $lower_limit = 1;

    db2_bind_param($stmt, 1, "lower_limit", DB2_PARAM_IN);
    db2_bind_param($stmt, 2, "upper_limit", DB2_PARAM_IN);

    // We can also declare the variable after calling db2_bind_param()
    $upper_limit = 15.0;

    if (db2_execute($stmt)) {
        while ($row = db2_fetch_array($stmt)) {
            print "{$row[0]}, {$row[1]}, {$row[2]}\n";
        }
    }
    ?>

以上例程会输出：

    Pook, cat, 3.2
    Rickety Ride, goat, 9.7
    Peaches, dog, 12.3

Example #2 Calling stored procedures with IN and OUT parameters

The stored procedure match_animal in the following example accepts three different parameters:

1. an input (IN) parameter that accepts the name of the first animal as input

2. an input-output (INOUT) parameter that accepts the name of the second animal as input and returns the string TRUE if an animal in the database matches that name

3. an output (OUT) parameter that returns the sum of the weight of the two identified animals

In addition, the stored procedure returns a result set consisting of the animals listed in alphabetic order starting at the animal corresponding to the input value of the first parameter and ending at the animal corresponding to the input value of the second parameter.

    <?php

    $sql = 'CALL match_animal(?, ?, ?)';
    $conn = db2_connect($database, $user, $password);
    $stmt = db2_prepare($conn, $sql);

    $name = "Peaches";
    $second_name = "Rickety Ride";
    $weight = 0;

    db2_bind_param($stmt, 1, "name", DB2_PARAM_IN);
    db2_bind_param($stmt, 2, "second_name", DB2_PARAM_INOUT);
    db2_bind_param($stmt, 3, "weight", DB2_PARAM_OUT);

    print "Values of bound parameters _before_ CALL:\n";
    print "  1: {$name} 2: {$second_name} 3: {$weight}\n\n";

    if (db2_execute($stmt)) {
        print "Values of bound parameters _after_ CALL:\n";
        print "  1: {$name} 2: {$second_name} 3: {$weight}\n\n";

        print "Results:\n";
        while ($row = db2_fetch_array($stmt)) {
            print "  {$row[0]}, {$row[1]}, {$row[2]}\n";
        }
    }
    ?>

以上例程会输出：

    Values of bound parameters _before_ CALL:
      1: Peaches 2: Rickety Ride 3: 0

    Values of bound parameters _after_ CALL:
      1: Peaches 2: TRUE 3: 22

    Results:
      Peaches, dog, 12.3
      Pook, cat, 3.2
      Rickety Ride, goat, 9.7

Example #3 Inserting a binary large object (BLOB) directly from a file

The data for large objects are typically stored in files, such as XML documents or audio files. Rather than reading an entire file into a PHP variable, and then binding that PHP variable into an SQL statement, you can avoid some memory overhead by binding the file directly to the input parameter of your SQL statement. The following example demonstrates how to bind a file directly into a BLOB column.

    <?php
    $stmt = db2_prepare($conn, "INSERT INTO animal_pictures(picture) VALUES (?)");

    $picture = "/opt/albums/spook/grooming.jpg";
    $rc = db2_bind_param($stmt, 1, "picture", DB2_PARAM_FILE);
    $rc = db2_execute($stmt);
    ?>

### 参见

- db2_execute() - Executes a prepared SQL statement
- db2_prepare() - Prepares an SQL statement to be executed