Schema Manager

• class SchemaManager(model[, database=None[, **context_options]])

Parameters:

• model (Model) – Model class.
• database (Database) – If unspecified defaults to model._meta.database.

Provides methods for managing the creation and deletion of tables andindexes for the given model.

• createtable([_safe=True[, **options]])

Parameters:

- **safe** (_bool_) – Specify IF NOT EXISTS clause.
- **options** – Arbitrary options.

Execute CREATE TABLE query for the given model.

• droptable([_safe=True[, drop_sequences=True[, **options]]])

Parameters:

- **safe** (_bool_) – Specify IF EXISTS clause.
- **drop_sequences** (_bool_) – Drop any sequences associated with thecolumns on the table (postgres only).
- **options** – Arbitrary options.

Execute DROP TABLE query for the given model.

• truncatetable([_restart_identity=False[, cascade=False]])

Parameters:

- **restart_identity** (_bool_) – Restart the id sequence (postgres-only).
- **cascade** (_bool_) – Truncate related tables as well (postgres-only).

Execute TRUNCATE TABLE for the given model. If the database is Sqlite,which does not support TRUNCATE, then an equivalent DELETE query willbe executed.

• createindexes([_safe=True])

Parameters:safe (bool) – Specify IF NOT EXISTS clause.

Execute CREATE INDEX queries for the indexes defined for the model.

• dropindexes([_safe=True])

Parameters:safe (bool) – Specify IF EXISTS clause.

Execute DROP INDEX queries for the indexes defined for the model.

• createsequence(_field)

Parameters:field (Field) – Field instance which specifies a sequence.

Create sequence for the given Field.

• dropsequence(_field)

Parameters:field (Field) – Field instance which specifies a sequence.

Drop sequence for the given Field.

• createforeign_key(_field)

Parameters:field (ForeignKeyField) – Foreign-key field constraint to add.

Add a foreign-key constraint for the given field. This method shouldnot be necessary in most cases, as foreign-key constraints are createdas part of table creation. The exception is when you are creating acircular foreign-key relationship using DeferredForeignKey.In those cases, it is necessary to first create the tables, then addthe constraint for the deferred foreign-key:

class Language(Model):
    name = TextField()
    selected_snippet = DeferredForeignKey('Snippet')
 
class Snippet(Model):
    code = TextField()
    language = ForeignKeyField(Language, backref='snippets')
 
# Creates both tables but does not create the constraint for the
# Language.selected_snippet foreign key (because of the circular
# dependency).
db.create_tables([Language, Snippet])
 
# Explicitly create the constraint:
Language._schema.create_foreign_key(Language.selected_snippet)

For more information, see documentation on Circular foreign key dependencies.

Warning

Because SQLite has limited support for altering existing tables, itis not possible to add a foreign-key constraint to an existingSQLite table.

• createall([_safe=True[, **table_options]])

Parameters:safe (bool) – Whether to specify IF NOT EXISTS.

Create sequence(s), index(es) and table for the model.

• dropall([_safe=True[, drop_sequences=True[, **options]]])

Parameters:

- **safe** (_bool_) – Whether to specify IF EXISTS.
- **drop_sequences** (_bool_) – Drop any sequences associated with thecolumns on the table (postgres only).
- **options** – Arbitrary options.

Drop table for the model and associated indexes.