Django officially supports the following databases:
\nThere are also a number of database backends provided by third parties.
\nDjango attempts to support as many features as possible on all database\nbackends. However, not all database backends are alike, and we’ve had to make\ndesign decisions on which features to support and which assumptions we can make\nsafely.
\nThis file describes some of the features that might be relevant to Django\nusage. It is not intended as a replacement for server-specific documentation or\nreference manuals.
\nPersistent connections avoid the overhead of reestablishing a connection to\nthe database in each HTTP request. They’re controlled by the\nCONN_MAX_AGE parameter which defines the maximum lifetime of a\nconnection. It can be set independently for each database.
The default value is 0, preserving the historical behavior of closing the\ndatabase connection at the end of each request. To enable persistent\nconnections, set CONN_MAX_AGE to a positive integer of seconds. For\nunlimited persistent connections, set it to None.
Django opens a connection to the database when it first makes a database\nquery. It keeps this connection open and reuses it in subsequent requests.\nDjango closes the connection once it exceeds the maximum age defined by\nCONN_MAX_AGE or when it isn’t usable any longer.
In detail, Django automatically opens a connection to the database whenever it\nneeds one and doesn’t have one already — either because this is the first\nconnection, or because the previous connection was closed.
\nAt the beginning of each request, Django closes the connection if it has\nreached its maximum age. If your database terminates idle connections after\nsome time, you should set CONN_MAX_AGE to a lower value, so that\nDjango doesn’t attempt to use a connection that has been terminated by the\ndatabase server. (This problem may only affect very low traffic sites.)
At the end of each request, Django closes the connection if it has reached its\nmaximum age or if it is in an unrecoverable error state. If any database\nerrors have occurred while processing the requests, Django checks whether the\nconnection still works, and closes it if it doesn’t. Thus, database errors\naffect at most one request per each application’s worker thread; if the\nconnection becomes unusable, the next request gets a fresh connection.
\nSetting CONN_HEALTH_CHECKS to True can be used to improve the\nrobustness of connection reuse and prevent errors when a connection has been\nclosed by the database server which is now ready to accept and serve new\nconnections, e.g. after database server restart. The health check is performed\nonly once per request and only if the database is being accessed during the\nhandling of the request.
Since each thread maintains its own connection, your database must support at\nleast as many simultaneous connections as you have worker threads.
\nSometimes a database won’t be accessed by the majority of your views, for\nexample because it’s the database of an external system, or thanks to caching.\nIn such cases, you should set CONN_MAX_AGE to a low value or even\n0, because it doesn’t make sense to maintain a connection that’s unlikely\nto be reused. This will help keep the number of simultaneous connections to\nthis database small.
The development server creates a new thread for each request it handles,\nnegating the effect of persistent connections. Don’t enable them during\ndevelopment.
\nWhen Django establishes a connection to the database, it sets up appropriate\nparameters, depending on the backend being used. If you enable persistent\nconnections, this setup is no longer repeated every request. If you modify\nparameters such as the connection’s isolation level or time zone, you should\neither restore Django’s defaults at the end of each request, force an\nappropriate value at the beginning of each request, or disable persistent\nconnections.
\nIf a connection is created in a long-running process, outside of Django’s\nrequest-response cycle, the connection will remain open until explicitly\nclosed, or timeout occurs.
\nDjango assumes that all databases use UTF-8 encoding. Using other encodings may\nresult in unexpected behavior such as “value too long” errors from your\ndatabase for data that is valid in Django. See the database specific notes\nbelow for information on how to set up your database correctly.
\nDjango supports PostgreSQL 12 and higher. psycopg 3.1.8+ or psycopg2\n2.8.4+ is required, though the latest psycopg 3.1.8+ is recommended.
\n\n\nSee HOST for details.
To connect using a service name from the connection service file and a\npassword from the password file, you must specify them in the\nOPTIONS part of your database configuration in DATABASES:
settings.pyDATABASES = {\n "default": {\n "ENGINE": "django.db.backends.postgresql",\n "OPTIONS": {\n "service": "my_service",\n "passfile": ".my_pgpass",\n },\n }\n}\n.pg_service.conf[my_service]\nhost=localhost\nuser=USER\ndbname=NAME\nport=5432\n.my_pgpasslocalhost:5432:NAME:USER:PASSWORD\nThe PostgreSQL backend passes the content of OPTIONS as keyword\narguments to the connection constructor, allowing for more advanced control\nof driver behavior. All available parameters are described in detail in the\nPostgreSQL documentation.
Django needs the following parameters for its database connections:
\nclient_encoding: 'UTF8',
default_transaction_isolation: 'read committed' by default,\nor the value set in the connection options (see below),
If these parameters already have the correct values, Django won’t set them for\nevery new connection, which improves performance slightly. You can configure\nthem directly in postgresql.conf or more conveniently per database\nuser with ALTER ROLE.
Django will work just fine without this optimization, but each new connection\nwill do some additional queries to set these parameters.
\nLike PostgreSQL itself, Django defaults to the READ COMMITTED isolation\nlevel. If you need a higher isolation level such as REPEATABLE READ or\nSERIALIZABLE, set it in the OPTIONS part of your database\nconfiguration in DATABASES:
from django.db.backends.postgresql.psycopg_any import IsolationLevel\n\nDATABASES = {\n # ...\n "OPTIONS": {\n "isolation_level": IsolationLevel.SERIALIZABLE,\n },\n}\nIf you need to use a different role for database connections than the role use\nto establish the connection, set it in the OPTIONS part of your\ndatabase configuration in DATABASES:
DATABASES = {\n "default": {\n "ENGINE": "django.db.backends.postgresql",\n # ...\n "OPTIONS": {\n "assume_role": "my_application_role",\n },\n },\n}\nWith psycopg 3.1.8+, Django defaults to the client-side binding\ncursors. If you want to use the\nserver-side binding set it in the\nOPTIONS part of your database configuration in\nDATABASES:
DATABASES = {\n "default": {\n "ENGINE": "django.db.backends.postgresql",\n # ...\n "OPTIONS": {\n "server_side_binding": True,\n },\n },\n}\nThis option is ignored with psycopg2.
When specifying db_index=True on your model fields, Django typically\noutputs a single CREATE INDEX statement. However, if the database type\nfor the field is either varchar or text (e.g., used by CharField,\nFileField, and TextField), then Django will create\nan additional index that uses an appropriate PostgreSQL operator class\nfor the column. The extra index is necessary to correctly perform\nlookups that use the LIKE operator in their SQL, as is done with the\ncontains and startswith lookup types.
If you need to add a PostgreSQL extension (like hstore, postgis, etc.)\nusing a migration, use the\nCreateExtension operation.
When using QuerySet.iterator(), Django opens a server-side\ncursor. By default, PostgreSQL assumes that\nonly the first 10% of the results of cursor queries will be fetched. The query\nplanner spends less time planning the query and starts returning results\nfaster, but this could diminish performance if more than 10% of the results are\nretrieved. PostgreSQL’s assumptions on the number of rows retrieved for a\ncursor query is controlled with the cursor_tuple_fraction option.
Using a connection pooler in transaction pooling mode (e.g. PgBouncer)\nrequires disabling server-side cursors for that connection.
\nServer-side cursors are local to a connection and remain open at the end of a\ntransaction when AUTOCOMMIT is True. A\nsubsequent transaction may attempt to fetch more results from a server-side\ncursor. In transaction pooling mode, there’s no guarantee that subsequent\ntransactions will use the same connection. If a different connection is used,\nan error is raised when the transaction references the server-side cursor,\nbecause server-side cursors are only accessible in the connection in which they\nwere created.
One solution is to disable server-side cursors for a connection in\nDATABASES by setting DISABLE_SERVER_SIDE_CURSORS to True.
To benefit from server-side cursors in transaction pooling mode, you could set\nup another connection to the database in order to\nperform queries that use server-side cursors. This connection needs to either\nbe directly to the database or to a connection pooler in session pooling mode.
\nAnother option is to wrap each QuerySet using server-side cursors in an\natomic() block, because it disables autocommit\nfor the duration of the transaction. This way, the server-side cursor will only\nlive for the duration of the transaction.
Django uses PostgreSQL’s identity columns to store auto-incrementing primary\nkeys. An identity column is populated with values from a sequence that keeps\ntrack of the next available value. Manually assigning a value to an\nauto-incrementing field doesn’t update the field’s sequence, which might later\ncause a conflict. For example:
\n>>> from django.contrib.auth.models import User\n>>> User.objects.create(username="alice", pk=1)\n<User: alice>\n>>> # The sequence hasn't been updated; its next value is 1.\n>>> User.objects.create(username="bob")\nIntegrityError: duplicate key value violates unique constraint\n"auth_user_pkey" DETAIL: Key (id)=(1) already exists.\nIf you need to specify such values, reset the sequence afterward to avoid\nreusing a value that’s already in the table. The sqlsequencereset\nmanagement command generates the SQL statements to do that.
You can use the TEST['TEMPLATE'] setting to specify\na template (e.g. 'template0') from which to create a test database.
You can speed up test execution times by configuring PostgreSQL to be\nnon-durable.
\n\nDjango supports MariaDB 10.4 and higher.
\nTo use MariaDB, use the MySQL backend, which is shared between the two. See the\nMySQL notes for more details.
\nDjango supports MySQL 8.0.11 and higher.
\nDjango’s inspectdb feature uses the information_schema database, which\ncontains detailed data on all database schemas.
Django expects the database to support Unicode (UTF-8 encoding) and delegates to\nit the task of enforcing transactions and referential integrity. It is important\nto be aware of the fact that the two latter ones aren’t actually enforced by\nMySQL when using the MyISAM storage engine, see the next section.
\nMySQL has several storage engines. You can change the default storage engine\nin the server configuration.
\nMySQL’s default storage engine is InnoDB. This engine is fully transactional\nand supports foreign key references. It’s the recommended choice. However, the\nInnoDB autoincrement counter is lost on a MySQL restart because it does not\nremember the AUTO_INCREMENT value, instead recreating it as “max(id)+1”.\nThis may result in an inadvertent reuse of AutoField\nvalues.
The main drawbacks of MyISAM are that it doesn’t support transactions or\nenforce foreign-key constraints.
\nMySQL has a couple drivers that implement the Python Database API described in\nPEP 249:
\nmysqlclient is a native driver. It’s the recommended choice.
MySQL Connector/Python is a pure Python driver from Oracle that does not\nrequire the MySQL client library or any Python modules outside the standard\nlibrary.
These drivers are thread-safe and provide connection pooling.
\nIn addition to a DB API driver, Django needs an adapter to access the database\ndrivers from its ORM. Django provides an adapter for mysqlclient while MySQL\nConnector/Python includes its own.
\nDjango requires mysqlclient 1.4.3 or later.
\nMySQL Connector/Python is available from the download page.\nThe Django adapter is available in versions 1.1.X and later. It may not\nsupport the most recent releases of Django.
\nIf you plan on using Django’s timezone support,\nuse mysql_tzinfo_to_sql to load time zone tables into the MySQL database.\nThis needs to be done just once for your MySQL server, not per database.
\nYou can create your database using the command-line tools and this SQL:
\nCREATE DATABASE <dbname> CHARACTER SET utf8;\nThis ensures all tables and columns will use UTF-8 by default.
\nThe collation setting for a column controls the order in which data is sorted\nas well as what strings compare as equal. You can specify the db_collation\nparameter to set the collation name of the column for\nCharField and\nTextField.
The collation can also be set on a database-wide level and per-table. This is\ndocumented thoroughly in the MySQL documentation. In such cases, you must\nset the collation by directly manipulating the database settings or tables.\nDjango doesn’t provide an API to change them.
\nBy default, with a UTF-8 database, MySQL will use the\nutf8_general_ci collation. This results in all string equality\ncomparisons being done in a case-insensitive manner. That is, "Fred" and\n"freD" are considered equal at the database level. If you have a unique\nconstraint on a field, it would be illegal to try to insert both "aa" and\n"AA" into the same column, since they compare as equal (and, hence,\nnon-unique) with the default collation. If you want case-sensitive comparisons\non a particular column or table, change the column or table to use the\nutf8_bin collation.
Please note that according to MySQL Unicode Character Sets, comparisons for\nthe utf8_general_ci collation are faster, but slightly less correct, than\ncomparisons for utf8_unicode_ci. If this is acceptable for your application,\nyou should use utf8_general_ci because it is faster. If this is not acceptable\n(for example, if you require German dictionary order), use utf8_unicode_ci\nbecause it is more accurate.
Refer to the settings documentation.
\nConnection settings are used in this order:
\n\nIn other words, if you set the name of the database in OPTIONS,\nthis will take precedence over NAME, which would override\nanything in a MySQL option file.
Here’s a sample configuration which uses a MySQL option file:
\n# settings.py\nDATABASES = {\n "default": {\n "ENGINE": "django.db.backends.mysql",\n "OPTIONS": {\n "read_default_file": "/path/to/my.cnf",\n },\n }\n}\n# my.cnf\n[client]\ndatabase = NAME\nuser = USER\npassword = PASSWORD\ndefault-character-set = utf8\nSeveral other MySQLdb connection options may be useful, such as ssl,\ninit_command, and sql_mode.
sql_modeLink to this heading#The default value of the sql_mode option contains STRICT_TRANS_TABLES.\nThat option escalates warnings into errors when data are truncated upon\ninsertion, so Django highly recommends activating a strict mode for MySQL to\nprevent data loss (either STRICT_TRANS_TABLES or STRICT_ALL_TABLES).
If you need to customize the SQL mode, you can set the sql_mode variable\nlike other MySQL options: either in a config file or with the entry\n'init_command': "SET sql_mode='STRICT_TRANS_TABLES'" in the\nOPTIONS part of your database configuration in DATABASES.
When running concurrent loads, database transactions from different sessions\n(say, separate threads handling different requests) may interact with each\nother. These interactions are affected by each session’s transaction isolation\nlevel. You can set a connection’s isolation level with an\n'isolation_level' entry in the OPTIONS part of your database\nconfiguration in DATABASES. Valid values for\nthis entry are the four standard isolation levels:
'read uncommitted'
'read committed'
'repeatable read'
'serializable'
or None to use the server’s configured isolation level. However, Django\nworks best with and defaults to read committed rather than MySQL’s default,\nrepeatable read. Data loss is possible with repeatable read. In particular,\nyou may see cases where get_or_create()\nwill raise an IntegrityError but the object won’t appear in\na subsequent get() call.
When Django generates the schema, it doesn’t specify a storage engine, so\ntables will be created with whatever default storage engine your database\nserver is configured for. The easiest solution is to set your database server’s\ndefault storage engine to the desired engine.
\nIf you’re using a hosting service and can’t change your server’s default\nstorage engine, you have a couple of options.
\nAfter the tables are created, execute an ALTER TABLE statement to\nconvert a table to a new storage engine (such as InnoDB):
ALTER TABLE <tablename> ENGINE=INNODB;\nThis can be tedious if you have a lot of tables.
\nAnother option is to use the init_command option for MySQLdb prior to\ncreating your tables:
"OPTIONS": {\n "init_command": "SET default_storage_engine=INNODB",\n}\nThis sets the default storage engine upon connecting to the database.\nAfter your tables have been created, you should remove this option as it\nadds a query that is only needed during table creation to each database\nconnection.
\nThere are known issues in even the latest versions of MySQL that can cause the\ncase of a table name to be altered when certain SQL statements are executed\nunder certain conditions. It is recommended that you use lowercase table\nnames, if possible, to avoid any problems that might arise from this behavior.\nDjango uses lowercase table names when it auto-generates table names from\nmodels, so this is mainly a consideration if you are overriding the table name\nvia the db_table parameter.
Both the Django ORM and MySQL (when using the InnoDB storage engine) support database savepoints.
\nIf you use the MyISAM storage engine please be aware of the fact that you will\nreceive database-generated errors if you try to use the savepoint-related\nmethods of the transactions API. The reason\nfor this is that detecting the storage engine of a MySQL database/table is an\nexpensive operation so it was decided it isn’t worth to dynamically convert\nthese methods in no-op’s based in the results of such detection.
\nAny fields that are stored with VARCHAR column types may have their\nmax_length restricted to 255 characters if you are using unique=True\nfor the field. This affects CharField,\nSlugField. See the MySQL documentation for more\ndetails.
TextField limitationsLink to this heading#MySQL can index only the first N chars of a BLOB or TEXT column. Since\nTextField doesn’t have a defined length, you can’t mark it as\nunique=True. MySQL will report: “BLOB/TEXT column ‘<db_column>’ used in key\nspecification without a key length”.
MySQL can store fractional seconds, provided that the column definition\nincludes a fractional indication (e.g. DATETIME(6)).
Django will not upgrade existing columns to include fractional seconds if the\ndatabase server supports it. If you want to enable them on an existing database,\nit’s up to you to either manually update the column on the target database, by\nexecuting a command like:
\nALTER TABLE `your_table` MODIFY `your_datetime_column` DATETIME(6)\nor using a RunSQL operation in a\ndata migration.
TIMESTAMP columnsLink to this heading#If you are using a legacy database that contains TIMESTAMP columns, you must\nset USE_TZ = False to avoid data corruption.\ninspectdb maps these columns to\nDateTimeField and if you enable timezone support,\nboth MySQL and Django will attempt to convert the values from UTC to local time.
QuerySet.select_for_update()Link to this heading#MySQL and MariaDB do not support some options to the SELECT ... FOR UPDATE\nstatement. If select_for_update() is used with an unsupported option, then\na NotSupportedError is raised.
Option | \nMariaDB | \nMySQL | \n
|---|---|---|
| \nX (≥10.6) | \nX | \n
| \nX | \nX | \n
| \n\n | X | \n
| \n\n | \n |
When using select_for_update() on MySQL, make sure you filter a queryset\nagainst at least a set of fields contained in unique constraints or only\nagainst fields covered by indexes. Otherwise, an exclusive write lock will be\nacquired over the full table for the duration of the transaction.
When performing a query on a string type, but with an integer value, MySQL will\ncoerce the types of all values in the table to an integer before performing the\ncomparison. If your table contains the values 'abc', 'def' and you\nquery for WHERE mycolumn=0, both rows will match. Similarly, WHERE mycolumn=1\nwill match the value 'abc1'. Therefore, string type fields included in Django\nwill always cast the value to a string before using it in a query.
If you implement custom model fields that inherit from\nField directly, are overriding\nget_prep_value(), or use\nRawSQL,\nextra(), or\nraw(), you should ensure that you perform\nappropriate typecasting.
Django supports SQLite 3.27.0 and later.
\nSQLite_는 주로 읽기 전용이거나 더 작은 설치 공간이 필요한 애플리케이션을 위한 훌륭한 개발 대안을 제공합니다. 하지만 모든 데이터베이스 서버와 마찬가지로 SQLite에만 적용되는 몇 가지 차이점이 있으므로 주의해야 합니다.
\n모든 SQLite 버전에서 일부 유형의 문자열을 매칭할 때 다소 반직관적인 동작이 있습니다. 이러한 동작은 쿼리 집합에서 iexact 또는 contains 필터를 사용할 때 트리거됩니다. 이 동작은 두 가지 경우로 나뉩니다:
1. For substring matching, all matches are done case-insensitively. That is a\nfilter such as filter(name__contains="aa") will match a name of "Aabb".
2. For strings containing characters outside the ASCII range, all exact string\nmatches are performed case-sensitively, even when the case-insensitive options\nare passed into the query. So the iexact filter will behave exactly\nthe same as the exact filter in these cases.
이에 대한 몇 가지 가능한 해결 방법은 ‘sqlite.org`_에 문서화되어 있지만, 이를 통합하는 것이 상당히 어렵기 때문에 장고의 기본 SQLite 백엔드에서는 활용되지 않습니다. 따라서 장고는 기본 SQLite 동작을 노출하며 대소문자를 구분하지 않거나 하위 문자열 필터링을 수행할 때 이를 알고 있어야 합니다.
\nSQLite에는 실수 소수점 내장 타입이 없습니다. 소수점 값은 내부적으로 SQLite 데이터 유형 문서``에 설명된 대로 ``REAL 데이터 타입(8바이트 IEEE 부동 소수점 숫자)으로 변환되므로 올바르게 반올림된 소수점 부동 소수점 산술을 지원하지 않습니다.
SQLite는 경량 데이터베이스를 위한 것이므로 높은 수준의 동시성을 지원할 수 없습니다. ‘운영 오류: 데이터베이스가 잠겼습니다 오류는 애플리케이션에서 ``sqlite``가 기본 구성에서 처리할 수 있는 것보다 더 많은 동시성이 발생하고 있음을 나타냅니다. 이 오류는 한 스레드 또는 프로세스가 데이터베이스 연결에 대한 독점 잠금을 가지고 있고 다른 스레드가 잠금이 해제되기를 기다리는 동안 시간이 초과되었음을 의미합니다.
Python의 SQLite 래퍼에는 두 번째 스레드가 시간 초과되어 ‘OperationalError: 데이터베이스가 잠겨 있습니다’라는 오류가 발생하기 전에 잠금을 대기할 수 있는 시간을 결정하는 기본 시간 초과 값이 있습니다.
\n이 오류가 발생하면 다음 방법으로 해결할 수 있습니다:
\n다른 데이터베이스 백엔드로 전환. 특정 시점에 이르면 SQLite는 실제 애플리케이션을 사용하기에 너무 “가벼워지며”, 이러한 종류의 동시성 오류는 그 시점에 도달했음을 나타냅니다.
코드를 다시 작성하여 동시성을 줄이고 데이터베이스 트랜잭션의 수명을 단축합니다.
‘시간 제한 데이터베이스 옵션을 설정하여 기본 시간 제한 값을 늘립니다:
"OPTIONS": {\n # ...\n "timeout": 20,\n # ...\n}\n이렇게 하면 SQLite가 “데이터베이스가 잠겼습니다.” 오류를 발생시키기 전에 조금 더 기다리게 되지만, 실제로 오류를 해결하는 데는 아무런 도움이 되지 않습니다.
\nQuerySet.select_for_update() 지원되지 않음Link to this heading#SQLite는 SELECT ... FOR UPDATE 구문을 지원하지 않습니다. 이 구문을 호출해도 아무런 효과가 없습니다.
QuerySet.iterator() 사용 시 격리Link to this heading#meth:`.QuerySet.iterator`를 사용하여 테이블을 순회하면서 수정할 때는 `Isolation In SQLite`_에 설명된 특별한 고려 사항이 있습니다. 루프 내에서 행이 추가, 변경 또는 삭제되면 해당 행이 이터레이터에서 가져온 후속 결과에 나타나거나 나타나지 않을 수도 있고 두 번 나타날 수도 있습니다. 코드에서 이를 처리해야 합니다.
\nSQLite에서 JSONField`를 사용하려면 Python의 :py:mod:`sqlite3 라이브러리에서 JSON1 확장`_을 활성화해야 합니다. 설치 시 이 확장이 활성화되어 있지 않으면 시스템 오류(``fields.E180`)가 발생합니다.
JSON1 확장을 활성화하려면 `위키 페이지`_의 지침을 따르세요.
\n\nDjango supports Oracle Database Server versions 19c and higher. Version\n1.3.2 or higher of the oracledb Python driver is required.
\n\nIn order for the python manage.py migrate command to work, your Oracle\ndatabase user must have privileges to run the following commands:
CREATE TABLE
CREATE SEQUENCE
CREATE PROCEDURE
CREATE TRIGGER
To run a project’s test suite, the user usually needs these additional\nprivileges:
\nCREATE USER
ALTER USER
DROP USER
CREATE TABLESPACE
DROP TABLESPACE
CREATE SESSION WITH ADMIN OPTION
CREATE TABLE WITH ADMIN OPTION
CREATE SEQUENCE WITH ADMIN OPTION
CREATE PROCEDURE WITH ADMIN OPTION
CREATE TRIGGER WITH ADMIN OPTION
While the RESOURCE role has the required CREATE TABLE,\nCREATE SEQUENCE, CREATE PROCEDURE, and CREATE TRIGGER privileges,\nand a user granted RESOURCE WITH ADMIN OPTION can grant RESOURCE, such\na user cannot grant the individual privileges (e.g. CREATE TABLE), and thus\nRESOURCE WITH ADMIN OPTION is not usually sufficient for running tests.
Some test suites also create views or materialized views; to run these, the\nuser also needs CREATE VIEW WITH ADMIN OPTION and\nCREATE MATERIALIZED VIEW WITH ADMIN OPTION privileges. In particular, this\nis needed for Django’s own test suite.
All of these privileges are included in the DBA role, which is appropriate\nfor use on a private developer’s database.
\nThe Oracle database backend uses the SYS.DBMS_LOB and SYS.DBMS_RANDOM\npackages, so your user will require execute permissions on it. It’s normally\naccessible to all users by default, but in case it is not, you’ll need to grant\npermissions like so:
GRANT EXECUTE ON SYS.DBMS_LOB TO user;\nGRANT EXECUTE ON SYS.DBMS_RANDOM TO user;\nTo connect using the service name of your Oracle database, your settings.py\nfile should look something like this:
DATABASES = {\n "default": {\n "ENGINE": "django.db.backends.oracle",\n "NAME": "xe",\n "USER": "a_user",\n "PASSWORD": "a_password",\n "HOST": "",\n "PORT": "",\n }\n}\nIn this case, you should leave both HOST and PORT empty.\nHowever, if you don’t use a tnsnames.ora file or a similar naming method\nand want to connect using the SID (“xe” in this example), then fill in both\nHOST and PORT like so:
DATABASES = {\n "default": {\n "ENGINE": "django.db.backends.oracle",\n "NAME": "xe",\n "USER": "a_user",\n "PASSWORD": "a_password",\n "HOST": "dbprod01ned.mycompany.com",\n "PORT": "1540",\n }\n}\nYou should either supply both HOST and PORT, or leave\nboth as empty strings. Django will use a different connect descriptor depending\non that choice.
A Full DSN or Easy Connect string can be used in NAME if both\nHOST and PORT are empty. This format is required when\nusing RAC or pluggable databases without tnsnames.ora, for example.
Example of an Easy Connect string:
\n"NAME": "localhost:1521/orclpdb1"\nExample of a full DSN string:
\n"NAME": (\n "(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521))"\n "(CONNECT_DATA=(SERVICE_NAME=orclpdb1)))"\n)\nIf you plan to run Django in a multithreaded environment (e.g. Apache using the\ndefault MPM module on any modern operating system), then you must set\nthe threaded option of your Oracle database configuration to True:
"OPTIONS": {\n "threaded": True,\n}\nFailure to do this may result in crashes and other odd behavior.
\nBy default, the Oracle backend uses a RETURNING INTO clause to efficiently\nretrieve the value of an AutoField when inserting new rows. This behavior\nmay result in a DatabaseError in certain unusual setups, such as when\ninserting into a remote table, or into a view with an INSTEAD OF trigger.\nThe RETURNING INTO clause can be disabled by setting the\nuse_returning_into option of the database configuration to False:
"OPTIONS": {\n "use_returning_into": False,\n}\nIn this case, the Oracle backend will use a separate SELECT query to\nretrieve AutoField values.
Oracle imposes a name length limit of 30 characters. To accommodate this, the\nbackend truncates database identifiers to fit, replacing the final four\ncharacters of the truncated name with a repeatable MD5 hash value.\nAdditionally, the backend turns database identifiers to all-uppercase.
\nTo prevent these transformations (this is usually required only when dealing\nwith legacy databases or accessing tables which belong to other users), use\na quoted name as the value for db_table:
class LegacyModel(models.Model):\n class Meta:\n db_table = '"name_left_in_lowercase"'\n\n\nclass ForeignModel(models.Model):\n class Meta:\n db_table = '"OTHER_USER"."NAME_ONLY_SEEMS_OVER_30"'\nQuoted names can also be used with Django’s other supported database\nbackends; except for Oracle, however, the quotes have no effect.
\nWhen running migrate, an ORA-06552 error may be encountered if\ncertain Oracle keywords are used as the name of a model field or the\nvalue of a db_column option. Django quotes all identifiers used\nin queries to prevent most such problems, but this error can still\noccur when an Oracle datatype is used as a column name. In\nparticular, take care to avoid using the names date,\ntimestamp, number or float as a field name.
Django generally prefers to use the empty string ('') rather than\nNULL, but Oracle treats both identically. To get around this, the\nOracle backend ignores an explicit null option on fields that\nhave the empty string as a possible value and generates DDL as if\nnull=True. When fetching from the database, it is assumed that\na NULL value in one of these fields really means the empty\nstring, and the data is silently converted to reflect this assumption.
TextField limitationsLink to this heading#The Oracle backend stores TextFields as NCLOB columns. Oracle imposes\nsome limitations on the usage of such LOB columns in general:
LOB columns may not be used as primary keys.
LOB columns may not be used in indexes.
LOB columns may not be used in a SELECT DISTINCT list. This means that\nattempting to use the QuerySet.distinct method on a model that\nincludes TextField columns will result in an ORA-00932 error when\nrun against Oracle. As a workaround, use the QuerySet.defer method in\nconjunction with distinct() to prevent TextField columns from being\nincluded in the SELECT DISTINCT list.
Django comes with built-in database backends. You may subclass an existing\ndatabase backends to modify its behavior, features, or configuration.
\nConsider, for example, that you need to change a single database feature.\nFirst, you have to create a new directory with a base module in it. For\nexample:
mysite/\n ...\n mydbengine/\n __init__.py\n base.py\nThe base.py module must contain a class named DatabaseWrapper that\nsubclasses an existing engine from the django.db.backends module. Here’s an\nexample of subclassing the PostgreSQL engine to change a feature class\nallows_group_by_selected_pks_on_model:
mysite/mydbengine/base.pyfrom django.db.backends.postgresql import base, features\n\n\nclass DatabaseFeatures(features.DatabaseFeatures):\n def allows_group_by_selected_pks_on_model(self, model):\n return True\n\n\nclass DatabaseWrapper(base.DatabaseWrapper):\n features_class = DatabaseFeatures\nFinally, you must specify a DATABASE-ENGINE in your settings.py\nfile:
DATABASES = {\n "default": {\n "ENGINE": "mydbengine",\n # ...\n },\n}\nYou can see the current list of database engines by looking in\ndjango/db/backends.
\nIn addition to the officially supported databases, there are backends provided\nby 3rd parties that allow you to use other databases with Django:
\n\nThe Django versions and ORM features supported by these unofficial backends\nvary considerably. Queries regarding the specific capabilities of these\nunofficial backends, along with any support queries, should be directed to\nthe support channels provided by each 3rd party project.
\n