Docs For Class Migrator

Description

The Migrator class executes migration files - PHP files with MDB2 instructions for database schema changes.

With migrations you have a versioning scheme for database schema changes and you can always go back and forward to a known database schema - on all of your database servers (development, production and test). The currect schema version number is stored in a special table in your database.

author: Gabriel Birke <birke@d-scribe.de>

Located in /migrator.php (line 28)

Class Constant Summary

ERROR_CLASS_NOT_FOUND = 5

ERROR_DB_CONNECT_FAILED = 2

ERROR_DB_QUERY_FAILED = 3

ERROR_INVALID_FILE_NAME = 4

ERROR_MIGRATION_DIR_MISSING = 1

ERROR_NO_MIGRATION_FILES = 6

VERSION = "0.7"

Variable Summary

MDB2_Driver $db

string $dsn

Log $logger

string $migrations_dir

array $migration_files

int $migration_max_version

string $schema_version_table

int $target_version

Method Summary

Migrator __construct (string $dsn, $target_version, string $migrations_dir, Log $logger, int $target)

void checkDBResult (MDB2_Result $result)

void collectMigrationFiles ()

void connect ()

void filterAndSortMigrationFiles (string $direction)

void getMigrationDirection ()

void initializeCurrentSchemaVersion ()

void log ( $message, [ $level = "debug"])

void migrate (string $direction)

int migrationFileNumber (string $filename)

void run ()

void writeNewMigrationVersion ( $newVersion)

boolean _filter_downgrade (string $filename)

boolean _filter_upgrade (string $filename)

Variables

MDB2_Driver $db (line 83)

access: protected

string $dsn (line 60)

Data Source Name

Example for a valid data source: mysql://my_user:my_pass@localhost/mydb

link: http://pear.php.net/manual/en/package.database.mdb2.intro-dsn.php
access: protected

Log $logger (line 89)

PEAR_Log or similar object

access: protected

string $migrations_dir (line 50)

Directory where th migration files are stored

access: protected

array $migration_files (line 66)

Filenames, sorted by number prefix

access: protected

int $migration_max_version (line 72)

Highest number prefix in $migration_files

access: protected

string $schema_version_table = "schema_version" (line 44)

Table name where the schema versions are stored

access: public

int $target_version (line 78)

Version to up/downgrade to

access: protected

Methods

Constructor __construct (line 101)

Initialize the internal variables.

If you subclass Migrator, you must call this constructor!

Migrator __construct (string $dsn, $target_version, string $migrations_dir, Log $logger, int $target)

string $dsn: Data Source Name
int $target: Version to up- or downgrade to (-1 for most recent version)
string $migrations_dir: Directory path where the the migration files are
Log $logger: PEAR_Log or similar object (must implement debug, error, notice and info methods)
$target_version

checkDBResult (line 346)

If the result given is an error, throw an exception.

access: protected

void checkDBResult (MDB2_Result $result)

MDB2_Result $result

collectMigrationFiles (line 154)

Collects migration file names from $migrations_dir and stores them in the sorted array $migration_files.

$migration_max_version is set to the biggest migration file prefix number.

access: protected

void collectMigrationFiles ()

connect (line 173)

Initializes $db with an instance of a MDB2 database driver.

The MDB2 "Manager" module is also loaded for the driver.

access: protected

void connect ()

filterAndSortMigrationFiles (line 230)

Leave only files in $this->migration_files that are needen for up/downgrade.

access: protected

void filterAndSortMigrationFiles (string $direction)

string $direction: "up" or "down"

getMigrationDirection (line 211)

access: protected

void getMigrationDirection ()

initializeCurrentSchemaVersion (line 189)

Initializes $current_version with version number from $schema_version_table.

If the table doesn't exist, initialize with 0 and create the table.

access: protected

void initializeCurrentSchemaVersion ()

log (line 353)

void log ( $message, [ $level = "debug"])

$message
$level

migrate (line 247)

Load each class in $migration_files and call its "up" or "down" method

access: protected

void migrate (string $direction)

string $direction: "up" or "down"

migrationFileNumber (line 309)

Return the migration file number at the start of a filename.

access: protected

int migrationFileNumber (string $filename)

string $filename

run (line 131)

The main function that does the migration.

Connects to the database, reads the current schema version, decides to up- or downgrade, loads the matching migrations, executes them and updates the schema version.

void run ()

writeNewMigrationVersion (line 296)

Write the new version number into {$schema_version_table}.

access: protected

void writeNewMigrationVersion ( $newVersion)

$newVersion

_filter_downgrade (line 335)

Callback function for http://www.php.net/array_filter that returns true for migration files between $target_version and $current_version.

access: protected

boolean _filter_downgrade (string $filename)

string $filename

_filter_upgrade (line 322)

Callback function for http://www.php.net/array_filter that returns true for migration files between $current_version and $target_version.

access: protected

boolean _filter_upgrade (string $filename)

string $filename

Class Constants

ERROR_CLASS_NOT_FOUND = 5 (line 37)

ERROR_DB_CONNECT_FAILED = 2 (line 34)

ERROR_DB_QUERY_FAILED = 3 (line 35)

ERROR_INVALID_FILE_NAME = 4 (line 36)

ERROR_MIGRATION_DIR_MISSING = 1 (line 33)

ERROR_NO_MIGRATION_FILES = 6 (line 38)

VERSION = "0.7" (line 30)