sqlalchemy.databases.postgresql.PGDialect

Undocumented

Undocumented

Return the string name of the currently selected schema from the given connection.

This is used by the default implementation to populate the "default_schema_name" attribute and is called exactly once upon first connect.

Undocumented

Retrieve the server version info from the given connection.

This is used by the default implementation to populate the "server_version_info" attribute and is called exactly once upon first connect.

Undocumented

Undocumented

Undocumented

Return information about check constraints in table_name.

Given a string table_name and an optional string schema, return check constraint information as a list of dicts with these keys:

• name - the check constraint's name
• sqltext - the check constraint's SQL expression
• **kw - other options passed to the dialect's get_check_constraints() method.

Return information about columns in table_name.

Given a _engine.Connection, a string table_name, and an optional string schema, return column information as a list of dictionaries with these keys:

name

the column's name

type

[sqlalchemy.types#TypeEngine]

nullable

boolean

default

the column's default value

autoincrement

boolean

sequence

a dictionary of the form

{'name' : str, 'start' :int, 'increment': int, 'minvalue': int,

'maxvalue': int, 'nominvalue': bool, 'nomaxvalue': bool, 'cycle': bool, 'cache': int, 'order': bool}

Additional column attributes may be present.

Undocumented

Return information about foreign_keys in table_name.

Given a _engine.Connection, a string table_name, and an optional string schema, return foreign key information as a list of dicts with these keys:

name

the constraint's name

constrained_columns

a list of column names that make up the foreign key

referred_schema

the name of the referred schema

referred_table

the name of the referred table

referred_columns

a list of column names in the referred table that correspond to constrained_columns

Return information about indexes in table_name.

Given a _engine.Connection, a string table_name and an optional string schema, return index information as a list of dictionaries with these keys:

name

the index's name

column_names

list of column names in order

unique

boolean

Given a DBAPI connection, return its isolation level.

When working with a _engine.Connection object, the corresponding DBAPI connection may be procured using the _engine.Connection.connection accessor.

Note that this is a dialect-level method which is used as part of the implementation of the _engine.Connection and _engine.Engine isolation level facilities; these APIs should be preferred for most typical use cases.

Return information about the primary key constraint on table_name`.

Given a _engine.Connection, a string table_name, and an optional string schema, return primary key information as a dictionary with these keys:

constrained_columns

a list of column names that make up the primary key

name

optional name of the primary key constraint.

Undocumented

Undocumented

Return a list of all sequence names available in the database.

Return the "comment" for the table identified by table_name.

Given a string table_name and an optional string schema, return table comment information as a dictionary with this key:

text

text of the comment

Raises NotImplementedError for dialects that don't support comments.

Fetch the oid for schema.table_name.

Several reflection methods require the table oid. The idea for using this method is that it can be fetched one time and cached for subsequent calls.

Return information about unique constraints in table_name.

Given a string table_name and an optional string schema, return unique constraint information as a list of dicts with these keys:

name

the unique constraint's name

column_names

list of column names in order

**kw

other options passed to the dialect's get_unique_constraints() method.

Return view definition.

Given a _engine.Connection, a string view_name, and an optional string schema, return the view definition.

Undocumented

Check the existence of a particular sequence in the database.

Given a _engine.Connection object and a string sequence_name, return True if the given sequence exists in the database, False otherwise.

For internal dialect use, check the existence of a particular table in the database.

Given a _engine.Connection object, a string table_name and optional schema name, return True if the given table exists in the database, False otherwise.

This method serves as the underlying implementation of the public facing .Inspector.has_table method, and is also used internally to implement the "checkfirst" behavior for methods like _schema.Table.create and _schema.MetaData.create_all.

Undocumented

Called during strategized creation of the dialect with a connection.

Allows dialects to configure options based on server version info or other properties.

The connection passed here is a SQLAlchemy Connection object, with full capabilities.

The initialize() method of the base dialect should be called via super().

return a callable which sets up a newly created DBAPI connection.

The callable should accept a single argument "conn" which is the DBAPI connection itself. The inner callable has no return value.

E.g.:

class MyDialect(default.DefaultDialect):
    # ...

    def on_connect(self):
        def do_on_connect(connection):
            connection.execute("SET SPECIAL FLAGS etc")

        return do_on_connect

This is used to set dialect-wide per-connection options such as isolation modes, Unicode modes, etc.

The "do_on_connect" callable is invoked by using the _events.PoolEvents.connect event hook, then unwrapping the DBAPI connection and passing it into the callable.

If None is returned, no event listener is generated.

Undocumented

Given a DBAPI connection, set its isolation level.

Note that this is a dialect-level method which is used as part of the implementation of the _engine.Connection and _engine.Engine isolation level facilities; these APIs should be preferred for most typical use cases.

Undocumented