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[multi-db] Added preliminary drop-table generation to django.db.backends.ansi.sql.SchemaBuilder.
git-svn-id: http://code.djangoproject.com/svn/django/branches/multiple-db-support@3320 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Jason Pellerin
parent
3e562344ab
commit
c0132e88f6
@ -43,8 +43,13 @@ class SchemaBuilder(object):
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or other constraints.
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"""
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def __init__(self):
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# models that I have created
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self.models_already_seen = set()
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# model references, keyed by the referrent model
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self.references = {}
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# table cache; set to short-circuit table lookups
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self.tables = None
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def get_create_table(self, model, style=None):
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"""Construct and return the SQL expression(s) needed to create the
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table for the given model, and any constraints on that
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@ -218,8 +223,8 @@ class SchemaBuilder(object):
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def get_drop_table(self, model, cascade=False, style=None):
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"""Construct and return the SQL statment(s) needed to drop a model's
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table. If cascade is true, then output additional statments to drop any
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dependant man-many tables and drop any foreign keys that reference
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this table.
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many-to-many tables that this table created and any foreign keys that
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reference this table.
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"""
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if style is None:
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style = default_style
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@ -227,16 +232,45 @@ class SchemaBuilder(object):
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info = opts.connection_info
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db_table = opts.db_table
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backend = info.backend
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qn = backend.quote_name
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output = []
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output.append(BoundStatement(
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'%s %s;' % (style.SQL_KEYWORD('DROP TABLE'),
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style.SQL_TABLE(backend.quote_name(db_table))),
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style.SQL_TABLE(qn(db_table))),
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info.connection))
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if cascade:
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# FIXME deal with my foreign keys, others that might have a foreign
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# key TO me, and many-many
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pass
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# deal with others that might have a foreign key TO me: alter
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# their tables to drop the constraint
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if backend.supports_constraints:
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references_to_delete = self.get_references()
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if model in references_to_delete:
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for rel_class, f in references_to_delete[model]:
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table = rel_class._meta.db_table
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if not self.table_exists(info, table):
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continue
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col = f.column
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r_table = opts.db_table
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r_col = opts.get_field(f.rel.field_name).column
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output.append(BoundStatement(
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'%s %s %s %s;' %
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(style.SQL_KEYWORD('ALTER TABLE'),
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style.SQL_TABLE(qn(table)),
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style.SQL_KEYWORD(
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backend.get_drop_foreignkey_sql()),
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style.SQL_FIELD(qn("%s_referencing_%s_%s" %
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(col, r_table, r_col)))),
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info.connection))
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del references_to_delete[model]
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# many to many: drop any many-many tables that are my
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# responsiblity
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for f in opts.many_to_many:
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if not isinstance(f.rel, models.GenericRel):
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output.append(BoundStatement(
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'%s %s;' %
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(style.SQL_KEYWORD('DROP TABLE'),
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style.SQL_TABLE(qn(f.m2m_db_table()))),
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info.connection))
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# Reverse it, to deal with table dependencies.
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output.reverse()
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return output
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@ -273,11 +307,36 @@ class SchemaBuilder(object):
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def get_initialdata_path(self, model):
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"""Get the path from which to load sql initial data files for a model.
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"""
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return os.path.normpath(os.path.join(os.path.dirname(models.get_app(model._meta.app_label).__file__), 'sql'))
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return os.path.normpath(os.path.join(os.path.dirname(
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models.get_app(model._meta.app_label).__file__), 'sql'))
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def get_rel_data_type(self, f):
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return (f.get_internal_type() in ('AutoField', 'PositiveIntegerField',
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'PositiveSmallIntegerField')) \
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and 'IntegerField' \
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or f.get_internal_type()
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def get_references(self):
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"""Fill (if needed) and return the reference cache.
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"""
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if self.references:
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return self.references
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for klass in models.get_models():
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for f in klass._meta.fields:
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if f.rel:
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self.references.setdefault(f.rel.to, []).append((klass, f))
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return self.references
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def get_table_list(self, connection_info):
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"""Get list of tables accessible via the connection described by
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connection_info.
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"""
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if self.tables is not None:
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return self.tables
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cursor = info.connection.cursor()
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introspection = connection_info.get_introspection_module()
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return introspection.get_table_list(cursor)
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def table_exists(self, connection_info, table):
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tables = self.get_table_list(connection_info)
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return table in tables
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@ -159,9 +159,8 @@ class Manager(object):
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"""Get list of tables accessible via my model's connection.
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"""
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info = self.model._meta.connection_info
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cursor = info.connection.cursor()
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introspect = info.get_introspection_module()
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return introspect.get_table_list(cursor)
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builder = info.get_creation_module.builder()
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return builder.get_table_list(info)
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class ManagerDescriptor(object):
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# This class ensures managers aren't accessible via model instances.
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@ -1,52 +1,24 @@
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# For Python 2.3
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if not hasattr(__builtins__, 'set'):
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from sets import Set as set
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"""
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>>> from django.db import models
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>>> from django.db.backends.ansi import sql
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# test models
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>>> class Car(models.Model):
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... make = models.CharField(maxlength=32)
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... model = models.CharField(maxlength=32)
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... year = models.IntegerField()
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... condition = models.CharField(maxlength=32)
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...
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... class Meta:
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... app_label = 'ansi_sql'
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>>> class Collector(models.Model):
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... name = models.CharField(maxlength=32)
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... cars = models.ManyToManyField(Car)
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...
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... class Meta:
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... app_label = 'ansi_sql'
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>>> class Mod(models.Model):
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... car = models.ForeignKey(Car)
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... part = models.CharField(maxlength=32, db_index=True)
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... description = models.TextField()
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...
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... class Meta:
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... app_label = 'ansi_sql'
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# so we can test with a predicatable constraint setting
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>>> real_cnst = Mod._meta.connection_info.backend.supports_constraints
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>>> Mod._meta.connection_info.backend.supports_constraints = True
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# generate create sql
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>>> builder = sql.SchemaBuilder()
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>>> builder.get_create_table(Car)
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([BoundStatement('CREATE TABLE "ansi_sql_car" (...);')], [])
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([BoundStatement('CREATE TABLE "ansi_sql_car" (...);')], {})
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>>> builder.models_already_seen
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[<class 'othertests.ansi_sql.Car'>]
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Set([<class 'othertests.ansi_sql.Car'>])
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>>> builder.models_already_seen = set()
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# test that styles are used
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>>> builder.get_create_table(Car, style=mockstyle())
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([BoundStatement('SQL_KEYWORD(CREATE TABLE) SQL_TABLE("ansi_sql_car") (...SQL_FIELD("id")...);')], [])
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([BoundStatement('SQL_KEYWORD(CREATE TABLE) SQL_TABLE("ansi_sql_car") (...SQL_FIELD("id")...);')], {})
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# test pending relationships
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>>> builder.models_already_seen = set()
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>>> real_cnst = Mod._meta.connection_info.backend.supports_constraints
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>>> Mod._meta.connection_info.backend.supports_constraints = True
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>>> builder.get_create_table(Mod)
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([BoundStatement('CREATE TABLE "ansi_sql_mod" (..."car_id" integer NOT NULL,...);')], {<class 'othertests.ansi_sql.Car'>: [BoundStatement('ALTER TABLE "ansi_sql_mod" ADD CONSTRAINT ... FOREIGN KEY ("car_id") REFERENCES "ansi_sql_car" ("id");')]})
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>>> builder.models_already_seen = set()
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@ -54,7 +26,6 @@ if not hasattr(__builtins__, 'set'):
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([BoundStatement('CREATE TABLE "ansi_sql_car" (...);')], {})
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>>> builder.get_create_table(Mod)
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([BoundStatement('CREATE TABLE "ansi_sql_mod" (..."car_id" integer NOT NULL REFERENCES "ansi_sql_car" ("id"),...);')], {})
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>>> Mod._meta.connection_info.backend.supports_constraints = real_cnst
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# test many-many
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>>> builder.get_create_table(Collector)
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@ -75,16 +46,82 @@ if not hasattr(__builtins__, 'set'):
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>>> builder.get_initialdata_path = othertests_sql
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>>> builder.get_initialdata(Car)
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[BoundStatement('insert into ansi_sql_car (...)...values (...);')]
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# test drop
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>>> builder.get_drop_table(Mod)
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[BoundStatement('DROP TABLE "ansi_sql_mod";')]
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>>> builder.get_drop_table(Mod, cascade=True)
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[BoundStatement('DROP TABLE "ansi_sql_mod";')]
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>>> builder.get_drop_table(Car)
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[BoundStatement('DROP TABLE "ansi_sql_car";')]
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>>> builder.get_drop_table(Car, cascade=True)
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[BoundStatement('DROP TABLE "ansi_sql_car";')]
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>>> builder.tables = ['ansi_sql_car', 'ansi_sql_mod', 'ansi_sql_collector']
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>>> Mod._meta.connection_info.backend.supports_constraints = False
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>>> builder.get_drop_table(Car, cascade=True)
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[BoundStatement('DROP TABLE "ansi_sql_car";')]
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>>> Mod._meta.connection_info.backend.supports_constraints = True
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>>> builder.get_drop_table(Car, cascade=True)
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[BoundStatement('ALTER TABLE "ansi_sql_mod" ...'), BoundStatement('DROP TABLE "ansi_sql_car";')]
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>>> builder.get_drop_table(Collector)
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[BoundStatement('DROP TABLE "ansi_sql_collector";')]
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>>> builder.get_drop_table(Collector, cascade=True)
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[BoundStatement('DROP TABLE "ansi_sql_collector_cars";'), BoundStatement('DROP TABLE "ansi_sql_collector";')]
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>>> Mod._meta.connection_info.backend.supports_constraints = real_cnst
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"""
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import os
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from django.db import models
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from django.core.management import install
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# For Python 2.3
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if not hasattr(__builtins__, 'set'):
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from sets import Set as set
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# test models
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class Car(models.Model):
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make = models.CharField(maxlength=32)
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model = models.CharField(maxlength=32)
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year = models.IntegerField()
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condition = models.CharField(maxlength=32)
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class Meta:
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app_label = 'ansi_sql'
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class Collector(models.Model):
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name = models.CharField(maxlength=32)
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cars = models.ManyToManyField(Car)
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class Meta:
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app_label = 'ansi_sql'
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class Mod(models.Model):
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car = models.ForeignKey(Car)
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part = models.CharField(maxlength=32, db_index=True)
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description = models.TextField()
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class Meta:
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app_label = 'ansi_sql'
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# mock style that wraps text in STYLE(text), for testing
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class mockstyle:
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"""mock style that wraps text in STYLE(text), for testing"""
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def __getattr__(self, attr):
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if attr in ('ERROR', 'ERROR_OUTPUT', 'SQL_FIELD', 'SQL_COLTYPE',
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'SQL_KEYWORD', 'SQL_TABLE'):
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return lambda text: "%s(%s)" % (attr, text)
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def othertests_sql(mod):
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"""Look in othertests/sql for sql initialdata"""
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return os.path.normpath(os.path.join(os.path.dirname(__file__), 'sql'))
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# install my stuff
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Car.objects.install()
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Collector.objects.install()
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Mod.objects.install()
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