| | 1 | == Extension Point : ''IDatabaseConnector'' == |
| | 2 | |
| | 3 | ||'''Interface'''||''IDatabaseConnector''||'''Since'''||[wiki:TracDev/ReleaseNotes/0.10#Improvedmodularity 0.10]|| |
| | 4 | ||'''Module'''||''trac.db''||'''Source'''||[source:trunk/trac/db/api.py api.py]|| |
| | 5 | |
| | 6 | |
| | 7 | The ''IDatabaseConnector'' allows supporting different [DatabaseBackend database backends]. |
| | 8 | |
| | 9 | == Purpose == |
| | 10 | |
| | 11 | Trac provides generic database abstraction layer, allowing extensible support for different database backends. This allows Trac to be used with either SQLite, MySQL, PostgreSQL or any other database for which a connector is available. |
| | 12 | |
| | 13 | == Usage == |
| | 14 | |
| | 15 | Implementing the interface follows the standard guidelines found in [wiki:TracDev/ComponentArchitecture] and of course [wiki:TracDev/PluginDevelopment]. |
| | 16 | |
| | 17 | Typically, an implementation checks if any required binding libraries are available when loaded. On failure, an error can be indicated when Trac queries the supported ''schemes''. The schema of the [wiki:TracEnvironment#DatabaseConnectionStrings database connection string] selects the appropriate implementation to be used. |
| | 18 | |
| | 19 | Primarily, the implementation then provides [pep:0249 Python DB API 2.0] ''connection'' and ''cursor'' objects for that connection string. Typically a `ConnectionWrapper` is used to wrap the connection object of the specific db library. |
| | 20 | |
| | 21 | Implementations also initialize and backup a database, and generate implementation specific DDL and SQL for poorly standardized features (like type casting, string concatenation, pattern matching, accessing the last row id). |
| | 22 | |
| | 23 | == Examples == |
| | 24 | |
| | 25 | Due to the complexity of implementing a full database backend, no simple example can be provided here. |
| | 26 | |
| | 27 | == Available Implementations == |
| | 28 | |
| | 29 | * Official Trac connectors |
| | 30 | * SQLite: [source:trunk/trac/db/sqlite_backend.py trac.db.sqlite_backend.SQLiteConnector] |
| | 31 | * PostgreSQL: [source:trunk/trac/db/postgres_backend.py trac.db.postgres_backend.PostgreSQLConnector] |
| | 32 | * MySQL: [source:trunk/trac/db/mysql_backend.py trac.db.mysql_backend.MySQLConnector] |
| | 33 | |
| | 34 | == Additional Information and References == |
| | 35 | |
| | 36 | * [http://www.edgewall.org/docs/trac-trunk/epydoc/trac.db.api.IDatabaseConnector-class.html epydoc] |
| | 37 | * [http://www.edgewall.org/docs/trac-trunk/html/api/trac_db.html#trac.db.IDatabaseConnector API Reference] |
| | 38 | * DatabaseBackend |
| | 39 | * Tickets relating to: |
| | 40 | * [query:status=!closed&keywords=~sql sql] |
| | 41 | * [query:status=!closed&keywords=~database database] |
| | 42 | * [query:status=!closed&keywords=~db db] |
| | 43 | * [query:status=!closed&component=database+backend database backend] component |
| | 44 | |
| | 45 | * About connectors for other databases |
| | 46 | * Oracle: #1874, th:ticket:5487 |
| | 47 | * Ingres: #6235 |
| | 48 | * Microsoft SQL Server: #329 |
| | 49 | * Generic ODBC: comment:21:ticket:329 |
| | 50 | |
| | 51 | * About replacing the DB abstraction layer: |
| | 52 | * [DatabaseBackend#AlternativeIdeasforDatabaseIndependence alternative ideas] |
| | 53 | * with Django: #6339 |
| | 54 | * with SqlAlchemy: [TracSqlAlchemy old plan], [browser:sandbox/Attic/sqlalchemy-ng retired branch] |
