SQLite Functions

简介

This is an extension for the SQLite Embeddable SQL Database Engine. SQLite is a C library that implements an embeddable SQL database engine. Programs that link with the SQLite library can have SQL database access without running a separate RDBMS process.

SQLite is not a client library used to connect to a big database server. SQLite is the server. The SQLite library reads and writes directly to and from the database files on disk.

Note: For further information see the SQLite Website (» http://sqlite.org/).

Installation

Read the INSTALL file, which comes with the package. Or just use the PEAR installer with pecl install sqlite. SQLite itself is already included, You do not need to install any additional software.

Windows users may download the DLL version of the SQLite extension here: (» php_sqlite.dll).

In PHP 5, the SQLite extension and the engine itself are bundled and compiled by default. However, since PHP 5.1.0 you need to manually activate the extension in php.ini (because it is now bundled as shared). Moreover, since PHP 5.1.0 SQLite depends on PDO it must be enabled too, by adding the following lines to php.ini (in order):

extension=php_pdo.dll
extension=php_sqlite.dll

SQLite 3 is supported through PDO SQLite.

Note: Windows installation for unprivileged accounts On Windows operating systems, unprivileged accounts don't have the TMP environment variable set by default. This will make sqlite create temporary files in the windows directory, which is not desirable. So, you should set the TMP environment variable for the web server or the user account the web server is running under. If Apache is your web server, you can accomplish this via a SetEnv directive in your httpd.conf file. For example:

SetEnv TMP c:/temp

If you are unable to establish this setting at the server level, you can implement the setting in your script:

putenv('TMP=C:/temp');

The setting must refer to a directory that the web server has permission to create files in and subsequently write to and delete the files it created. Otherwise, you may receive the following error message: malformed database schema - unable to open a temporary database file for storing temporary tables

需求

In order to have these functions available, you must compile PHP with SQLite support, or load the SQLite extension dynamically from your php.ini.

资源类型

There are two resources used in the SQLite Interface. The first one is the database connection, the second one the result set.

预定义常量

以下常量由本扩展模块定义，因此只有在本扩展模块被编译到 PHP 中，或者在运行时被动态加载后才有效。

The functions sqlite_fetch_array() and sqlite_current() use a constant for the different types of result arrays. The following constants are defined:

SQLite result type constants

SQLITE_ASSOC (int)

Columns are returned into the array having the field name as the array index.

SQLITE_BOTH (int)

Columns are returned into the array having both a numerical index and the field name as the array index.

SQLITE_NUM (int)

Columns are returned into the array having a numerical index to the fields. This index starts with 0, the first field in the result.

A number of functions may return status codes. The following constants are defined:

SQLite status code constants

SQLITE_OK (int)

Successful result.

SQLITE_ERROR (int)

SQL error or missing database.

SQLITE_INTERNAL (int)

An internal logic error in SQLite.

SQLITE_PERM (int)

Access permission denied.

SQLITE_ABORT (int)

Callback routine requested an abort.

SQLITE_BUSY (int)

The database file is locked.

SQLITE_LOCKED (int)

A table in the database is locked.

SQLITE_NOMEM (int)

Memory allocation failed.

SQLITE_READONLY (int)

Attempt to write a readonly database.

SQLITE_INTERRUPT (int)

Operation terminated internally.

SQLITE_IOERR (int)

Disk I/O error occurred.

SQLITE_CORRUPT (int)

The database disk image is malformed.

SQLITE_NOTFOUND (int)

(Internal) Table or record not found.

SQLITE_FULL (int)

Insertion failed because database is full.

SQLITE_CANTOPEN (int)

Unable to open the database file.

SQLITE_PROTOCOL (int)

Database lock protocol error.

SQLITE_EMPTY (int)

(Internal) Database table is empty.

SQLITE_SCHEMA (int)

The database schema changed.

SQLITE_TOOBIG (int)

Too much data for one row of a table.

SQLITE_CONSTRAINT (int)

Abort due to constraint violation.

SQLITE_MISMATCH (int)

Data type mismatch.

SQLITE_MISUSE (int)

Library used incorrectly.

SQLITE_NOLFS (int)

Uses of OS features not supported on host.

SQLITE_AUTH (int)

Authorized failed.

SQLITE_ROW (int)

Internal process has another row ready.

SQLITE_DONE (int)

Internal process has finished executing.

预定义类

运行时配置

这些函数的行为受 php.ini 的影响。

以下是配置选项的简要解释。

sqlite.assoc_case int

Whether to use mixed case (0), upper case (1) or lower case (2) hash indexes.

This option is primarily useful when you need compatibility with other database systems, where the names of the columns are always returned as uppercase or lowercase, regardless of the case of the actual field names in the database schema.

The SQLite library returns the column names in their natural case (that matches the case you used in your schema). When sqlite.assoc_case is set to 0 the natural case will be preserved. When it is set to 1 or 2, PHP will apply case folding on the hash keys to upper- or lower-case the keys, respectively.

Use of this option incurs a slight performance penalty, but is MUCH faster than performing the case folding yourself using PHP script.