182 lines
7.7 KiB
Python
182 lines
7.7 KiB
Python
"""
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PostgreSQL database backend for Django.
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Requires psycopg 2: http://initd.org/projects/psycopg2
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"""
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from django.db.backends import BaseDatabaseWrapper, BaseDatabaseOperations, util
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try:
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import psycopg2 as Database
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import psycopg2.extensions
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except ImportError, e:
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured, "Error loading psycopg2 module: %s" % e
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DatabaseError = Database.DatabaseError
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IntegrityError = Database.IntegrityError
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psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
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postgres_version = None
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class DatabaseOperations(BaseDatabaseOperations):
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def date_extract_sql(self, lookup_type, field_name):
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# http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-EXTRACT
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return "EXTRACT('%s' FROM %s)" % (lookup_type, field_name)
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def date_trunc_sql(self, lookup_type, field_name):
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# http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
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return "DATE_TRUNC('%s', %s)" % (lookup_type, field_name)
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def deferrable_sql(self):
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return " DEFERRABLE INITIALLY DEFERRED"
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def last_insert_id(self, cursor, table_name, pk_name):
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cursor.execute("SELECT CURRVAL('\"%s_%s_seq\"')" % (table_name, pk_name))
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return cursor.fetchone()[0]
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def quote_name(self, name):
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if name.startswith('"') and name.endswith('"'):
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return name # Quoting once is enough.
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return '"%s"' % name
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def sql_flush(self, style, tables, sequences):
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qn = self.quote_name
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if tables:
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if postgres_version[0] >= 8 and postgres_version[1] >= 1:
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# Postgres 8.1+ can do 'TRUNCATE x, y, z...;'. In fact, it *has to*
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# in order to be able to truncate tables referenced by a foreign
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# key in any other table. The result is a single SQL TRUNCATE
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# statement.
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sql = ['%s %s;' % \
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(style.SQL_KEYWORD('TRUNCATE'),
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style.SQL_FIELD(', '.join([qn(table) for table in tables]))
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)]
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else:
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# Older versions of Postgres can't do TRUNCATE in a single call, so
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# they must use a simple delete.
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sql = ['%s %s %s;' % \
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(style.SQL_KEYWORD('DELETE'),
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style.SQL_KEYWORD('FROM'),
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style.SQL_FIELD(qn(table))
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) for table in tables]
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# 'ALTER SEQUENCE sequence_name RESTART WITH 1;'... style SQL statements
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# to reset sequence indices
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for sequence_info in sequences:
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table_name = sequence_info['table']
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column_name = sequence_info['column']
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if column_name and len(column_name)>0:
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# sequence name in this case will be <table>_<column>_seq
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sql.append("%s %s %s %s %s %s;" % \
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(style.SQL_KEYWORD('ALTER'),
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style.SQL_KEYWORD('SEQUENCE'),
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style.SQL_FIELD(qn('%s_%s_seq' % (table_name, column_name))),
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style.SQL_KEYWORD('RESTART'),
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style.SQL_KEYWORD('WITH'),
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style.SQL_FIELD('1')
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)
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)
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else:
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# sequence name in this case will be <table>_id_seq
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sql.append("%s %s %s %s %s %s;" % \
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(style.SQL_KEYWORD('ALTER'),
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style.SQL_KEYWORD('SEQUENCE'),
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style.SQL_FIELD(qn('%s_id_seq' % table_name)),
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style.SQL_KEYWORD('RESTART'),
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style.SQL_KEYWORD('WITH'),
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style.SQL_FIELD('1')
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)
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)
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return sql
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else:
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return []
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def sequence_reset_sql(self, style, model_list):
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from django.db import models
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qn = self.quote_name
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output = []
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for model in model_list:
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# Use `coalesce` to set the sequence for each model to the max pk value if there are records,
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# or 1 if there are none. Set the `is_called` property (the third argument to `setval`) to true
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# if there are records (as the max pk value is already in use), otherwise set it to false.
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for f in model._meta.fields:
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if isinstance(f, models.AutoField):
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output.append("%s setval('%s', coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
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(style.SQL_KEYWORD('SELECT'),
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style.SQL_FIELD(qn('%s_%s_seq' % (model._meta.db_table, f.column))),
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style.SQL_FIELD(qn(f.column)),
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style.SQL_FIELD(qn(f.column)),
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style.SQL_KEYWORD('IS NOT'),
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style.SQL_KEYWORD('FROM'),
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style.SQL_TABLE(qn(model._meta.db_table))))
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break # Only one AutoField is allowed per model, so don't bother continuing.
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for f in model._meta.many_to_many:
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output.append("%s setval('%s', coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
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(style.SQL_KEYWORD('SELECT'),
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style.SQL_FIELD(qn('%s_id_seq' % f.m2m_db_table())),
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style.SQL_FIELD(qn('id')),
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style.SQL_FIELD(qn('id')),
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style.SQL_KEYWORD('IS NOT'),
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style.SQL_KEYWORD('FROM'),
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style.SQL_TABLE(f.m2m_db_table())))
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return output
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class DatabaseWrapper(BaseDatabaseWrapper):
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ops = DatabaseOperations()
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def _cursor(self, settings):
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set_tz = False
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if self.connection is None:
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set_tz = True
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if settings.DATABASE_NAME == '':
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured, "You need to specify DATABASE_NAME in your Django settings file."
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conn_string = "dbname=%s" % settings.DATABASE_NAME
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if settings.DATABASE_USER:
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conn_string = "user=%s %s" % (settings.DATABASE_USER, conn_string)
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if settings.DATABASE_PASSWORD:
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conn_string += " password='%s'" % settings.DATABASE_PASSWORD
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if settings.DATABASE_HOST:
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conn_string += " host=%s" % settings.DATABASE_HOST
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if settings.DATABASE_PORT:
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conn_string += " port=%s" % settings.DATABASE_PORT
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self.connection = Database.connect(conn_string, **self.options)
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self.connection.set_isolation_level(1) # make transactions transparent to all cursors
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self.connection.set_client_encoding('UTF8')
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cursor = self.connection.cursor()
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cursor.tzinfo_factory = None
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if set_tz:
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cursor.execute("SET TIME ZONE %s", [settings.TIME_ZONE])
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global postgres_version
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if not postgres_version:
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cursor.execute("SELECT version()")
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postgres_version = [int(val) for val in cursor.fetchone()[0].split()[1].split('.')]
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return cursor
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allows_group_by_ordinal = True
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allows_unique_and_pk = True
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autoindexes_primary_keys = True
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needs_datetime_string_cast = False
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needs_upper_for_iops = False
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supports_constraints = True
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supports_tablespaces = False
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uses_case_insensitive_names = False
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OPERATOR_MAPPING = {
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'exact': '= %s',
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'iexact': 'ILIKE %s',
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'contains': 'LIKE %s',
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'icontains': 'ILIKE %s',
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'regex': '~ %s',
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'iregex': '~* %s',
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'gt': '> %s',
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'gte': '>= %s',
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'lt': '< %s',
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'lte': '<= %s',
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'startswith': 'LIKE %s',
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'endswith': 'LIKE %s',
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'istartswith': 'ILIKE %s',
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'iendswith': 'ILIKE %s',
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}
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