# IBM DB2, Cloudscape and Apache Derby Functions

## Introduction

These functions enable you to access IBM DB2 Universal Database, IBM Cloudscape, and Apache Derby databases using the DB2 Call Level Interface (DB2 CLI).

## Requirements

To connect to IBM DB2 Universal Database for Linux, UNIX, and Windows, or IBM Cloudscape, or Apache Derby, you must install an IBM DB2 Universal Database client on the same computer on which you are running PHP. The extension has been developed and tested with DB2 Version 8.2.

To connect to IBM DB2 Universal Database for z/OS or iSeries, you also require IBM DB2 Connect or the equivalent DRDA gateway software.

## Requirements on Linux or Unix

The user invoking the PHP executable or SAPI must specify the DB2 instance before accessing these functions. You can set the name of the DB2 instance in php.ini using the ibm_db2.instance_name configuration option, or you can source the DB2 instance profile before invoking the PHP executable.

If you created a DB2 instance named db2inst1 in /home/db2inst1/, for example, you can add the following line to php.ini:

    ibm_db2.instance_name=db2inst1

If you do not set this option in php.ini, you must issue the following command to modify your environment variables to enable access to DB2:

    bash$ source /home/db2inst1/sqllib/db2profile

To enable your PHP-enabled Web server to access these functions, you must either set the ibm_db2.instance_name configuration option in php.ini, or source the DB2 instance environment in your Web server start script (typically /etc/init.d/httpd or /etc/init.d/apache).

## Installation

To build the ibm_db2 extension, the DB2 application development header files and libraries must be installed on your system. DB2 does not install these by default, so you may have to return to your DB2 installer and add this option. The header files are included with the DB2 Application Development Client freely available for download from the IBM DB2 Universal Database » support site.

If you add the DB2 application development header files and libraries to a Linux or Unix operating system on which DB2 was already installed, you must issue the command db2iupdt -e to update the symbolic links to the header files and libraries in your DB2 instances.

ibm_db2 is a » PECL extension, so follow the instructions in Installation of PECL extensions to install the ibm_db2 extension for PHP. Issue the configure command to point to the location of your DB2 header files and libraries as follows:

    bash$ ./configure --with-IBM_DB2=/path/to/DB2

The configure command defaults to /opt/IBM/db2/V8.1.

> Note: Note for IIS users If you are using the ibm_db2 driver with Microsoft Internet Information Server (IIS) you may have to do the following:

> - Install DB2 with extended operating system security.
> - Add the PHP binary path to the PATH system environment variable (default C:\php\).
> - Create another system environment variable equal to the path where the PHP.INI file is located (eg: PHPRC = C:\php\).
> - Add the IUSR_COMPUTERNAME to the DB2USERS group.

## Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

ibm_db2 Configure Options
Name | Default | Changeable | Changelog
--- | --- | --- | ---
ibm_db2.binmode | "1" | PHP_INI_ALL |
ibm_db2.i5_allow_commit | "0" | PHP_INI_SYSTEM | Available since ibm_db2 1.4.9.
ibm_db2.i5_dbcs_alloc | "0" | PHP_INI_SYSTEM | Available since ibm_db2 1.5.0.
ibm_db2.instance_name | NULL | PHP_INI_SYSTEM | Available since ibm_db2 1.0.2.

Here's a short explanation of the configuration directives.

`ibm_db2.binmode` integer

  This option controls the mode used for converting to and from binary data in the PHP application.

  - 1 (DB2_BINARY)

  - 2 (DB2_CONVERT)

  - 3 (DB2_PASSTHRU)

`ibm_db2.i5_allow_commit` integer

  This option controls the commit mode used for i5 schema collections in the PHP application.

  - 0 no commit (see i5_commit for override)

  - 1 allow commit (see i5_commit for override)

`ibm_db2.i5_dbcs_alloc` integer

  This option controls the internal ibm_db2 allocation scheme for large DBCS column buffers.

  - 0 no expanded allocations (see i5_dbcs_alloc for override)

  - 1 use expanded allocations (see i5_dbcs_alloc for override)

`ibm_db2.instance_name` string

  On Linux and UNIX operating systems, this option defines the name of the instance to use for cataloged database connections. If this option is set, its value overrides the DB2INSTANCE environment variable setting.

  This option is ignored on Windows operating systems.

## Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

`DB2_BINARY` (integer)
  Specifies that binary data shall be returned as is. This is the default mode.
`DB2_CONVERT` (integer)
  Specifies that binary data shall be converted to a hexadecimal encoding and returned as an ASCII string.
`DB2_PASSTHRU` (integer)
  Specifies that binary data shall be converted to a `NULL` value.
`DB2_SCROLLABLE` (integer)
  Specifies a scrollable cursor for a statement resource. This mode enables random access to rows in a result set, but currently is supported only by IBM DB2 Universal Database.
`DB2_FORWARD_ONLY` (integer)
  Specifies a forward-only cursor for a statement resource. This is the default cursor type and is supported on all database servers.
`DB2_PARAM_IN` (integer)
  Specifies the PHP variable should be bound as an IN parameter for a stored procedure.
`DB2_PARAM_OUT` (integer)
  Specifies the PHP variable should be bound as an OUT parameter for a stored procedure.
`DB2_PARAM_INOUT` (integer)
  Specifies the PHP variable should be bound as an INOUT parameter for a stored procedure.
`DB2_PARAM_FILE` (integer)
  Specifies that the column should be bound directly to a file for input.
`DB2_AUTOCOMMIT_ON` (integer)
  Specifies that autocommit should be turned on.
`DB2_AUTOCOMMIT_OFF` (integer)
  Specifies that autocommit should be turned off.
`DB2_DOUBLE` (integer)
  Specifies that the variable should be bound as a DOUBLE, FLOAT, or REAL data type.
`DB2_LONG` (integer)
  Specifies that the variable should be bound as a SMALLINT, INTEGER, or BIGINT data type.
`DB2_CHAR` (integer)
  Specifies that the variable should be bound as a CHAR or VARCHAR data type.
`DB2_CASE_NATURAL` (integer)
  Specifies that column names will be returned in their natural case.
`DB2_CASE_LOWER` (integer)
  Specifies that column names will be returned in lower case.
`DB2_CASE_UPPER` (integer)
  Specifies that column names will be returned in upper case.
`DB2_DEFERRED_PREPARE_ON` (integer)
  Specifies that deferred prepare should be turned on for the specified statement resource.
`DB2_DEFERRED_PREPARE_OFF` (integer)
  Specifies that deferred prepare should be turned off for the specified statement resource.

## Resource Types

The ibm_db2 extension returns connection resources, statement resources, and result set resources.

## Table of Contents

- db2_autocommit — Returns or sets the AUTOCOMMIT state for a database connection
- db2_bind_param — Binds a PHP variable to an SQL statement parameter
- db2_client_info — Returns an object with properties that describe the DB2 database client
- db2_close — Closes a database connection
- db2_column_privileges — Returns a result set listing the columns and associated privileges for a table
- db2_columns — Returns a result set listing the columns and associated metadata for a table
- db2_commit — Commits a transaction
- db2_conn_error — Returns a string containing the SQLSTATE returned by the last connection attempt
- db2_conn_errormsg — Returns the last connection error message and SQLCODE value
- db2_connect — Returns a connection to a database
- db2_cursor_type — Returns the cursor type used by a statement resource
- db2_escape_string — Used to escape certain characters.
- db2_exec — Executes an SQL statement directly
- db2_execute — Executes a prepared SQL statement
- db2_fetch_array — Returns an array, indexed by column position, representing a row in a result set
- db2_fetch_assoc — Returns an array, indexed by column name, representing a row in a result set
- db2_fetch_both — Returns an array, indexed by both column name and position, representing a row in a result set
- db2_fetch_object — Returns an object with properties representing columns in the fetched row
- db2_fetch_row — Sets the result set pointer to the next row or requested row
- db2_field_display_size — Returns the maximum number of bytes required to display a column
- db2_field_name — Returns the name of the column in the result set
- db2_field_num — Returns the position of the named column in a result set
- db2_field_precision — Returns the precision of the indicated column in a result set
- db2_field_scale — Returns the scale of the indicated column in a result set
- db2_field_type — Returns the data type of the indicated column in a result set
- db2_field_width — Returns the width of the current value of the indicated column in a result set
- db2_foreign_keys — Returns a result set listing the foreign keys for a table
- db2_free_result — Frees resources associated with a result set
- db2_free_stmt — Frees resources associated with the indicated statement resource
- db2_get_option — Retrieves an option value for a statement resource or a connection resource
- db2_lob_read — Gets a user defined size of LOB files with each invocation
- db2_next_result — Requests the next result set from a stored procedure
- db2_num_fields — Returns the number of fields contained in a result set
- db2_num_rows — Returns the number of rows affected by an SQL statement
- db2_pconnect — Returns a persistent connection to a database
- db2_prepare — Prepares an SQL statement to be executed
- db2_primary_keys — Returns a result set listing primary keys for a table
- db2_procedure_columns — Returns a result set listing stored procedure parameters
- db2_procedures — Returns a result set listing the stored procedures registered in a database
- db2_result — Returns a single column from a row in the result set
- db2_rollback — Rolls back a transaction
- db2_server_info — Returns an object with properties that describe the DB2 database server
- db2_set_option — Set options for connection or statement resources
- db2_special_columns — Returns a result set listing the unique row identifier columns for a table
- db2_statistics — Returns a result set listing the index and statistics for a table
- db2_stmt_error — Returns a string containing the SQLSTATE returned by an SQL statement
- db2_stmt_errormsg — Returns a string containing the last SQL statement error message
- db2_table_privileges — Returns a result set listing the tables and associated privileges in a database
- db2_tables — Returns a result set listing the tables and associated metadata in a database