import sys
import time
try:
set
except NameError:
# Python 2.3 compat
from sets import Set
from django.conf import settings
from django.core.management import call_command
# The prefix to put on the default database name when creating
# the test database.
TEST_DATABASE_PREFIX = 'test_'
class BaseDatabaseCreation(object):
"""
This class encapsulates all backend-specific differences that pertain to
database *creation*, such as the column types to use for particular Django
Fields, the SQL used to create and destroy tables, and the creation and
destruction of test databases.
"""
data_types = {}
def __init__(self, connection):
self.connection = connection
def _digest(self, *args):
"""
Generates a 32-bit digest of a set of arguments that can be used to
shorten identifying names.
"""
return '%x' % (abs(hash(args)) % 4294967296L) # 2**32
def sql_create_model(self, model, style, known_models=set()):
"""
Returns the SQL required to create a single model, as a tuple of:
(list_of_sql, pending_references_dict)
"""
from django.db import models
opts = model._meta
if not opts.managed or opts.proxy:
return [], {}
final_output = []
table_output = []
pending_references = {}
qn = self.connection.ops.quote_name
for f in opts.local_fields:
col_type = f.db_type(connection=self.connection)
tablespace = f.db_tablespace or opts.db_tablespace
if col_type is None:
# Skip ManyToManyFields, because they're not represented as
# database columns in this table.
continue
# Make the definition (e.g. 'foo VARCHAR(30)') for this field.
field_output = [style.SQL_FIELD(qn(f.column)),
style.SQL_COLTYPE(col_type)]
if not f.null:
field_output.append(style.SQL_KEYWORD('NOT NULL'))
if f.primary_key:
field_output.append(style.SQL_KEYWORD('PRIMARY KEY'))
elif f.unique:
field_output.append(style.SQL_KEYWORD('UNIQUE'))
if tablespace and f.unique:
# We must specify the index tablespace inline, because we
# won't be generating a CREATE INDEX statement for this field.
field_output.append(self.connection.ops.tablespace_sql(tablespace, inline=True))
if f.rel:
ref_output, pending = self.sql_for_inline_foreign_key_references(f, known_models, style)
if pending:
pr = pending_references.setdefault(f.rel.to, []).append((model, f))
else:
field_output.extend(ref_output)
table_output.append(' '.join(field_output))
for field_constraints in opts.unique_together:
table_output.append(style.SQL_KEYWORD('UNIQUE') + ' (%s)' % \
", ".join([style.SQL_FIELD(qn(opts.get_field(f).column)) for f in field_constraints]))
full_statement = [style.SQL_KEYWORD('CREATE TABLE') + ' ' + style.SQL_TABLE(qn(opts.db_table)) + ' (']
for i, line in enumerate(table_output): # Combine and add commas.
full_statement.append(' %s%s' % (line, i < len(table_output)-1 and ',' or ''))
full_statement.append(')')
if opts.db_tablespace:
full_statement.append(self.connection.ops.tablespace_sql(opts.db_tablespace))
full_statement.append(';')
final_output.append('\n'.join(full_statement))
if opts.has_auto_field:
# Add any extra SQL needed to support auto-incrementing primary keys.
auto_column = opts.auto_field.db_column or opts.auto_field.name
autoinc_sql = self.connection.ops.autoinc_sql(opts.db_table, auto_column)
if autoinc_sql:
for stmt in autoinc_sql:
final_output.append(stmt)
return final_output, pending_references
def sql_for_inline_foreign_key_references(self, field, known_models, style):
"Return the SQL snippet defining the foreign key reference for a field"
qn = self.connection.ops.quote_name
if field.rel.to in known_models:
output = [style.SQL_KEYWORD('REFERENCES') + ' ' + \
style.SQL_TABLE(qn(field.rel.to._meta.db_table)) + ' (' + \
style.SQL_FIELD(qn(field.rel.to._meta.get_field(field.rel.field_name).column)) + ')' +
self.connection.ops.deferrable_sql()
]
pending = False
else:
# We haven't yet created the table to which this field
# is related, so save it for later.
output = []
pending = True
return output, pending
def sql_for_pending_references(self, model, style, pending_references):
"Returns any ALTER TABLE statements to add constraints after the fact."
from django.db.backends.util import truncate_name
if not model._meta.managed or model._meta.proxy:
return []
qn = self.connection.ops.quote_name
final_output = []
opts = model._meta
if model in pending_references:
for rel_class, f in pending_references[model]:
rel_opts = rel_class._meta
r_table = rel_opts.db_table
r_col = f.column
table = opts.db_table
col = opts.get_field(f.rel.field_name).column
# For MySQL, r_name must be unique in the first 64 characters.
# So we are careful with character usage here.
r_name = '%s_refs_%s_%s' % (r_col, col, self._digest(r_table, table))
final_output.append(style.SQL_KEYWORD('ALTER TABLE') + ' %s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s (%s)%s;' % \
(qn(r_table), qn(truncate_name(r_name, self.connection.ops.max_name_length())),
qn(r_col), qn(table), qn(col),
self.connection.ops.deferrable_sql()))
del pending_references[model]
return final_output
def sql_for_many_to_many(self, model, style):
"Return the CREATE TABLE statments for all the many-to-many tables defined on a model"
import warnings
warnings.warn(
'Database creation API for m2m tables has been deprecated. M2M models are now automatically generated',
PendingDeprecationWarning
)
output = []
for f in model._meta.local_many_to_many:
if model._meta.managed or f.rel.to._meta.managed:
output.extend(self.sql_for_many_to_many_field(model, f, style))
return output
def sql_for_many_to_many_field(self, model, f, style):
"Return the CREATE TABLE statements for a single m2m field"
import warnings
warnings.warn(
'Database creation API for m2m tables has been deprecated. M2M models are now automatically generated',
PendingDeprecationWarning
)
from django.db import models
from django.db.backends.util import truncate_name
output = []
if f.auto_created:
opts = model._meta
qn = self.connection.ops.quote_name
tablespace = f.db_tablespace or opts.db_tablespace
if tablespace:
sql = self.connection.ops.tablespace_sql(tablespace, inline=True)
if sql:
tablespace_sql = ' ' + sql
else:
tablespace_sql = ''
else:
tablespace_sql = ''
table_output = [style.SQL_KEYWORD('CREATE TABLE') + ' ' + \
style.SQL_TABLE(qn(f.m2m_db_table())) + ' (']
table_output.append(' %s %s %s%s,' %
(style.SQL_FIELD(qn('id')),
style.SQL_COLTYPE(models.AutoField(primary_key=True).db_type(connection=self.connection)),
style.SQL_KEYWORD('NOT NULL PRIMARY KEY'),
tablespace_sql))
deferred = []
inline_output, deferred = self.sql_for_inline_many_to_many_references(model, f, style)
table_output.extend(inline_output)
table_output.append(' %s (%s, %s)%s' %
(style.SQL_KEYWORD('UNIQUE'),
style.SQL_FIELD(qn(f.m2m_column_name())),
style.SQL_FIELD(qn(f.m2m_reverse_name())),
tablespace_sql))
table_output.append(')')
if opts.db_tablespace:
# f.db_tablespace is only for indices, so ignore its value here.
table_output.append(self.connection.ops.tablespace_sql(opts.db_tablespace))
table_output.append(';')
output.append('\n'.join(table_output))
for r_table, r_col, table, col in deferred:
r_name = '%s_refs_%s_%s' % (r_col, col, self._digest(r_table, table))
output.append(style.SQL_KEYWORD('ALTER TABLE') + ' %s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s (%s)%s;' %
(qn(r_table),
qn(truncate_name(r_name, self.connection.ops.max_name_length())),
qn(r_col), qn(table), qn(col),
self.connection.ops.deferrable_sql()))
# Add any extra SQL needed to support auto-incrementing PKs
autoinc_sql = self.connection.ops.autoinc_sql(f.m2m_db_table(), 'id')
if autoinc_sql:
for stmt in autoinc_sql:
output.append(stmt)
return output
def sql_for_inline_many_to_many_references(self, model, field, style):
"Create the references to other tables required by a many-to-many table"
import warnings
warnings.warn(
'Database creation API for m2m tables has been deprecated. M2M models are now automatically generated',
PendingDeprecationWarning
)
from django.db import models
opts = model._meta
qn = self.connection.ops.quote_name
table_output = [
' %s %s %s %s (%s)%s,' %
(style.SQL_FIELD(qn(field.m2m_column_name())),
style.SQL_COLTYPE(models.ForeignKey(model).db_type(connection=self.connection)),
style.SQL_KEYWORD('NOT NULL REFERENCES'),
style.SQL_TABLE(qn(opts.db_table)),
style.SQL_FIELD(qn(opts.pk.column)),
self.connection.ops.deferrable_sql()),
' %s %s %s %s (%s)%s,' %
(style.SQL_FIELD(qn(field.m2m_reverse_name())),
style.SQL_COLTYPE(models.ForeignKey(field.rel.to).db_type(connection=self.connection)),
style.SQL_KEYWORD('NOT NULL REFERENCES'),
style.SQL_TABLE(qn(field.rel.to._meta.db_table)),
style.SQL_FIELD(qn(field.rel.to._meta.pk.column)),
self.connection.ops.deferrable_sql())
]
deferred = []
return table_output, deferred
def sql_indexes_for_model(self, model, style):
"Returns the CREATE INDEX SQL statements for a single model"
if not model._meta.managed or model._meta.proxy:
return []
output = []
for f in model._meta.local_fields:
output.extend(self.sql_indexes_for_field(model, f, style))
return output
def sql_indexes_for_field(self, model, f, style):
"Return the CREATE INDEX SQL statements for a single model field"
from django.db.backends.util import truncate_name
if f.db_index and not f.unique:
qn = self.connection.ops.quote_name
tablespace = f.db_tablespace or model._meta.db_tablespace
if tablespace:
sql = self.connection.ops.tablespace_sql(tablespace)
if sql:
tablespace_sql = ' ' + sql
else:
tablespace_sql = ''
else:
tablespace_sql = ''
i_name = '%s_%s' % (model._meta.db_table, self._digest(f.column))
output = [style.SQL_KEYWORD('CREATE INDEX') + ' ' +
style.SQL_TABLE(qn(truncate_name(i_name, self.connection.ops.max_name_length()))) + ' ' +
style.SQL_KEYWORD('ON') + ' ' +
style.SQL_TABLE(qn(model._meta.db_table)) + ' ' +
"(%s)" % style.SQL_FIELD(qn(f.column)) +
"%s;" % tablespace_sql]
else:
output = []
return output
def sql_destroy_model(self, model, references_to_delete, style):
"Return the DROP TABLE and restraint dropping statements for a single model"
if not model._meta.managed or model._meta.proxy:
return []
# Drop the table now
qn = self.connection.ops.quote_name
output = ['%s %s;' % (style.SQL_KEYWORD('DROP TABLE'),
style.SQL_TABLE(qn(model._meta.db_table)))]
if model in references_to_delete:
output.extend(self.sql_remove_table_constraints(model, references_to_delete, style))
if model._meta.has_auto_field:
ds = self.connection.ops.drop_sequence_sql(model._meta.db_table)
if ds:
output.append(ds)
return output
def sql_remove_table_constraints(self, model, references_to_delete, style):
from django.db.backends.util import truncate_name
if not model._meta.managed or model._meta.proxy:
return []
output = []
qn = self.connection.ops.quote_name
for rel_class, f in references_to_delete[model]:
table = rel_class._meta.db_table
col = f.column
r_table = model._meta.db_table
r_col = model._meta.get_field(f.rel.field_name).column
r_name = '%s_refs_%s_%s' % (col, r_col, self._digest(table, r_table))
output.append('%s %s %s %s;' % \
(style.SQL_KEYWORD('ALTER TABLE'),
style.SQL_TABLE(qn(table)),
style.SQL_KEYWORD(self.connection.ops.drop_foreignkey_sql()),
style.SQL_FIELD(qn(truncate_name(r_name, self.connection.ops.max_name_length())))))
del references_to_delete[model]
return output
def sql_destroy_many_to_many(self, model, f, style):
"Returns the DROP TABLE statements for a single m2m field"
import warnings
warnings.warn(
'Database creation API for m2m tables has been deprecated. M2M models are now automatically generated',
PendingDeprecationWarning
)
qn = self.connection.ops.quote_name
output = []
if f.auto_created:
output.append("%s %s;" % (style.SQL_KEYWORD('DROP TABLE'),
style.SQL_TABLE(qn(f.m2m_db_table()))))
ds = self.connection.ops.drop_sequence_sql("%s_%s" % (model._meta.db_table, f.column))
if ds:
output.append(ds)
return output
def create_test_db(self, verbosity=1, autoclobber=False):
"""
Creates a test database, prompting the user for confirmation if the
database already exists. Returns the name of the test database created.
"""
if verbosity >= 1:
print "Creating test database '%s'..." % self.connection.alias
test_database_name = self._create_test_db(verbosity, autoclobber)
self.connection.close()
self.connection.settings_dict["NAME"] = test_database_name
can_rollback = self._rollback_works()
self.connection.settings_dict["SUPPORTS_TRANSACTIONS"] = can_rollback
call_command('syncdb', verbosity=verbosity, interactive=False, database=self.connection.alias)
if settings.CACHE_BACKEND.startswith('db://'):
from django.core.cache import parse_backend_uri
_, cache_name, _ = parse_backend_uri(settings.CACHE_BACKEND)
call_command('createcachetable', cache_name)
# Get a cursor (even though we don't need one yet). This has
# the side effect of initializing the test database.
cursor = self.connection.cursor()
return test_database_name
def _create_test_db(self, verbosity, autoclobber):
"Internal implementation - creates the test db tables."
suffix = self.sql_table_creation_suffix()
if self.connection.settings_dict['TEST_NAME']:
test_database_name = self.connection.settings_dict['TEST_NAME']
else:
test_database_name = TEST_DATABASE_PREFIX + self.connection.settings_dict['NAME']
qn = self.connection.ops.quote_name
# Create the test database and connect to it. We need to autocommit
# if the database supports it because PostgreSQL doesn't allow
# CREATE/DROP DATABASE statements within transactions.
cursor = self.connection.cursor()
self.set_autocommit()
try:
cursor.execute("CREATE DATABASE %s %s" % (qn(test_database_name), suffix))
except Exception, e:
sys.stderr.write("Got an error creating the test database: %s\n" % e)
if not autoclobber:
confirm = raw_input("Type 'yes' if you would like to try deleting the test database '%s', or 'no' to cancel: " % test_database_name)
if autoclobber or confirm == 'yes':
try:
if verbosity >= 1:
print "Destroying old test database..."
cursor.execute("DROP DATABASE %s" % qn(test_database_name))
if verbosity >= 1:
print "Creating test database..."
cursor.execute("CREATE DATABASE %s %s" % (qn(test_database_name), suffix))
except Exception, e:
sys.stderr.write("Got an error recreating the test database: %s\n" % e)
sys.exit(2)
else:
print "Tests cancelled."
sys.exit(1)
return test_database_name
def _rollback_works(self):
cursor = self.connection.cursor()
cursor.execute('CREATE TABLE ROLLBACK_TEST (X INT)')
self.connection._commit()
cursor.execute('INSERT INTO ROLLBACK_TEST (X) VALUES (8)')
self.connection._rollback()
cursor.execute('SELECT COUNT(X) FROM ROLLBACK_TEST')
count, = cursor.fetchone()
cursor.execute('DROP TABLE ROLLBACK_TEST')
self.connection._commit()
return count == 0
def destroy_test_db(self, old_database_name, verbosity=1):
"""
Destroy a test database, prompting the user for confirmation if the
database already exists. Returns the name of the test database created.
"""
if verbosity >= 1:
print "Destroying test database '%s'..." % self.connection.alias
self.connection.close()
test_database_name = self.connection.settings_dict['NAME']
self.connection.settings_dict['NAME'] = old_database_name
self._destroy_test_db(test_database_name, verbosity)
def _destroy_test_db(self, test_database_name, verbosity):
"Internal implementation - remove the test db tables."
# Remove the test database to clean up after
# ourselves. Connect to the previous database (not the test database)
# to do so, because it's not allowed to delete a database while being
# connected to it.
cursor = self.connection.cursor()
self.set_autocommit()
time.sleep(1) # To avoid "database is being accessed by other users" errors.
cursor.execute("DROP DATABASE %s" % self.connection.ops.quote_name(test_database_name))
self.connection.close()
def set_autocommit(self):
"Make sure a connection is in autocommit mode."
if hasattr(self.connection.connection, "autocommit"):
if callable(self.connection.connection.autocommit):
self.connection.connection.autocommit(True)
else:
self.connection.connection.autocommit = True
elif hasattr(self.connection.connection, "set_isolation_level"):
self.connection.connection.set_isolation_level(0)
def sql_table_creation_suffix(self):
"SQL to append to the end of the test table creation statements"
return ''
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