SQLAlchemy 1.1 Documentation
Core Internals¶
Some key internal constructs are listed here.
-
class
sqlalchemy.engine.interfaces.
Compiled
(dialect, statement, bind=None, schema_translate_map=None, compile_kwargs=immutabledict({}))¶ Represent a compiled SQL or DDL expression.
The
__str__
method of theCompiled
object should produce the actual text of the statement.Compiled
objects are specific to their underlying database dialect, and also may or may not be specific to the columns referenced within a particular set of bind parameters. In no case should theCompiled
object be dependent on the actual values of those bind parameters, even though it may reference those values as defaults.-
__init__
(dialect, statement, bind=None, schema_translate_map=None, compile_kwargs=immutabledict({}))¶ Construct a new
Compiled
object.매개 변수: - dialect¶ –
Dialect
to compile against. - statement¶ –
ClauseElement
to be compiled. - bind¶ – Optional Engine or Connection to compile this statement against.
- schema_translate_map¶ –
dictionary of schema names to be translated when forming the resultant SQL
버전 1.1에 추가.
- compile_kwargs¶ – additional kwargs that will be
passed to the initial call to
Compiled.process()
.
- dialect¶ –
-
compile
()¶ Produce the internal string representation of this element.
버전 0.7 폐지:
Compiled
objects now compile within the constructor.
-
construct_params
(params=None)¶ Return the bind params for this compiled object.
매개 변수: params¶ – a dict of string/object pairs whose values will override bind values compiled in to the statement.
-
execute
(*multiparams, **params)¶ Execute this compiled object.
-
params
¶ Return the bind params for this compiled object.
-
scalar
(*multiparams, **params)¶ Execute this compiled object and return the result’s scalar value.
-
sql_compiler
¶ Return a Compiled that is capable of processing SQL expressions.
If this compiler is one, it would likely just return ‘self’.
-
-
class
sqlalchemy.sql.compiler.
DDLCompiler
(dialect, statement, bind=None, schema_translate_map=None, compile_kwargs=immutabledict({}))¶ Bases:
sqlalchemy.sql.compiler.Compiled
-
__init__
(dialect, statement, bind=None, schema_translate_map=None, compile_kwargs=immutabledict({}))¶ - inherited from the
__init__()
method ofCompiled
Construct a new
Compiled
object.매개 변수: - dialect¶ –
Dialect
to compile against. - statement¶ –
ClauseElement
to be compiled. - bind¶ – Optional Engine or Connection to compile this statement against.
- schema_translate_map¶ –
dictionary of schema names to be translated when forming the resultant SQL
버전 1.1에 추가.
- compile_kwargs¶ – additional kwargs that will be
passed to the initial call to
Compiled.process()
.
- dialect¶ –
-
compile
()¶ - inherited from the
compile()
method ofCompiled
Produce the internal string representation of this element.
버전 0.7 폐지:
Compiled
objects now compile within the constructor.
-
define_constraint_remote_table
(constraint, table, preparer)¶ Format the remote table clause of a CREATE CONSTRAINT clause.
-
execute
(*multiparams, **params)¶ - inherited from the
execute()
method ofCompiled
Execute this compiled object.
-
params
¶ - inherited from the
params
attribute ofCompiled
Return the bind params for this compiled object.
-
scalar
(*multiparams, **params)¶ - inherited from the
scalar()
method ofCompiled
Execute this compiled object and return the result’s scalar value.
-
-
class
sqlalchemy.engine.default.
DefaultDialect
(convert_unicode=False, encoding='utf-8', paramstyle=None, dbapi=None, implicit_returning=None, supports_right_nested_joins=None, case_sensitive=True, supports_native_boolean=None, label_length=None, **kwargs)¶ Bases:
sqlalchemy.engine.interfaces.Dialect
Default implementation of Dialect
-
construct_arguments
= None¶ Optional set of argument specifiers for various SQLAlchemy constructs, typically schema items.
To implement, establish as a series of tuples, as in:
construct_arguments = [ (schema.Index, { "using": False, "where": None, "ops": None }) ]
If the above construct is established on the Postgresql dialect, the
Index
construct will now accept the keyword argumentspostgresql_using
,postgresql_where
, nadpostgresql_ops
. Any other argument specified to the constructor ofIndex
which is prefixed withpostgresql_
will raiseArgumentError
.A dialect which does not include a
construct_arguments
member will not participate in the argument validation system. For such a dialect, any argument name is accepted by all participating constructs, within the namespace of arguments prefixed with that dialect name. The rationale here is so that third-party dialects that haven’t yet implemented this feature continue to function in the old way.버전 0.9.2에 추가.
더 보기
DialectKWArgs
- implementing base class which consumesDefaultDialect.construct_arguments
-
create_xid
()¶ Create a random two-phase transaction ID.
This id will be passed to do_begin_twophase(), do_rollback_twophase(), do_commit_twophase(). Its format is unspecified.
-
dbapi_exception_translation_map
= immutabledict({})¶ mapping used in the extremely unusual case that a DBAPI’s published exceptions don’t actually have the __name__ that they are linked towards.
버전 1.0.5에 추가.
-
denormalize_name
(name)¶ - inherited from the
denormalize_name()
method ofDialect
convert the given name to a case insensitive identifier for the backend if it is an all-lowercase name.
this method is only used if the dialect defines requires_name_normalize=True.
-
do_begin_twophase
(connection, xid)¶ - inherited from the
do_begin_twophase()
method ofDialect
Begin a two phase transaction on the given connection.
매개 변수: - connection¶ – a
Connection
. - xid¶ – xid
- connection¶ – a
-
do_commit_twophase
(connection, xid, is_prepared=True, recover=False)¶ - inherited from the
do_commit_twophase()
method ofDialect
Commit a two phase transaction on the given connection.
매개 변수: - connection¶ – a
Connection
. - xid¶ – xid
- is_prepared¶ – whether or not
TwoPhaseTransaction.prepare()
was called. - recover¶ – if the recover flag was passed.
- connection¶ – a
-
do_prepare_twophase
(connection, xid)¶ - inherited from the
do_prepare_twophase()
method ofDialect
Prepare a two phase transaction on the given connection.
매개 변수: - connection¶ – a
Connection
. - xid¶ – xid
- connection¶ – a
-
do_recover_twophase
(connection)¶ - inherited from the
do_recover_twophase()
method ofDialect
Recover list of uncommited prepared two phase transaction identifiers on the given connection.
매개 변수: connection¶ – a Connection
.
-
do_rollback_twophase
(connection, xid, is_prepared=True, recover=False)¶ - inherited from the
do_rollback_twophase()
method ofDialect
Rollback a two phase transaction on the given connection.
매개 변수: - connection¶ – a
Connection
. - xid¶ – xid
- is_prepared¶ – whether or not
TwoPhaseTransaction.prepare()
was called. - recover¶ – if the recover flag was passed.
- connection¶ – a
-
engine_created
(engine)¶ - inherited from the
engine_created()
method ofDialect
A convenience hook called before returning the final
Engine
.If the dialect returned a different class from the
get_dialect_cls()
method, then the hook is called on both classes, first on the dialect class returned by theget_dialect_cls()
method and then on the class on which the method was called.The hook should be used by dialects and/or wrappers to apply special events to the engine or its components. In particular, it allows a dialect-wrapping class to apply dialect-level events.
버전 1.0.3에 추가.
-
execute_sequence_format
¶ alias of
tuple
-
get_columns
(connection, table_name, schema=None, **kw)¶ - inherited from the
get_columns()
method ofDialect
Return information about columns in table_name.
Given a
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}
Additional column attributes may be present.
-
get_dialect_cls
(url)¶ - inherited from the
get_dialect_cls()
method ofDialect
Given a URL, return the
Dialect
that will be used.This is a hook that allows an external plugin to provide functionality around an existing dialect, by allowing the plugin to be loaded from the url based on an entrypoint, and then the plugin returns the actual dialect to be used.
By default this just returns the cls.
버전 1.0.3에 추가.
-
get_foreign_keys
(connection, table_name, schema=None, **kw)¶ - inherited from the
get_foreign_keys()
method ofDialect
Return information about foreign_keys in table_name.
Given a
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
-
get_indexes
(connection, table_name, schema=None, **kw)¶ - inherited from the
get_indexes()
method ofDialect
Return information about indexes in table_name.
Given a
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
-
get_isolation_level
(dbapi_conn)¶ - inherited from the
get_isolation_level()
method ofDialect
Given a DBAPI connection, return its isolation level.
When working with a
Connection
object, the corresponding DBAPI connection may be procured using theConnection.connection
accessor.Note that this is a dialect-level method which is used as part of the implementation of the
Connection
andEngine
isolation level facilities; these APIs should be preferred for most typical use cases.더 보기
Connection.get_isolation_level()
- view current levelConnection.default_isolation_level
- view default levelConnection.execution_options.isolation_level
- set perConnection
isolation levelcreate_engine.isolation_level
- set perEngine
isolation level
-
get_pk_constraint
(conn, table_name, schema=None, **kw)¶ Compatibility method, adapts the result of get_primary_keys() for those dialects which don’t implement get_pk_constraint().
-
get_primary_keys
(connection, table_name, schema=None, **kw)¶ - inherited from the
get_primary_keys()
method ofDialect
Return information about primary keys in table_name.
Deprecated. This method is only called by the default implementation of
Dialect.get_pk_constraint()
. Dialects should instead implement theDialect.get_pk_constraint()
method directly.
-
get_table_names
(connection, schema=None, **kw)¶ - inherited from the
get_table_names()
method ofDialect
Return a list of table names for schema.
-
get_temp_table_names
(connection, schema=None, **kw)¶ - inherited from the
get_temp_table_names()
method ofDialect
Return a list of temporary table names on the given connection, if supported by the underlying backend.
-
get_temp_view_names
(connection, schema=None, **kw)¶ - inherited from the
get_temp_view_names()
method ofDialect
Return a list of temporary view names on the given connection, if supported by the underlying backend.
-
get_unique_constraints
(connection, table_name, schema=None, **kw)¶ - inherited from the
get_unique_constraints()
method ofDialect
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.
버전 0.9.0에 추가.
-
get_view_definition
(connection, view_name, schema=None, **kw)¶ - inherited from the
get_view_definition()
method ofDialect
Return view definition.
Given a
Connection
, a string view_name, and an optional string schema, return the view definition.
-
get_view_names
(connection, schema=None, **kw)¶ - inherited from the
get_view_names()
method ofDialect
Return a list of all view names available in the database.
- schema:
- Optional, retrieve names from a non-default schema.
-
has_sequence
(connection, sequence_name, schema=None)¶ - inherited from the
has_sequence()
method ofDialect
Check the existence of a particular sequence in the database.
Given a
Connection
object and a string sequence_name, return True if the given sequence exists in the database, False otherwise.
-
has_table
(connection, table_name, schema=None)¶ - inherited from the
has_table()
method ofDialect
Check the existence of a particular table in the database.
Given a
Connection
object and a string table_name, return True if the given table (possibly within the specified schema) exists in the database, False otherwise.
-
normalize_name
(name)¶ - inherited from the
normalize_name()
method ofDialect
convert the given name to lowercase if it is detected as case insensitive.
this method is only used if the dialect defines requires_name_normalize=True.
-
on_connect
()¶ return a callable which sets up a newly created DBAPI connection.
This is used to set dialect-wide per-connection options such as isolation modes, unicode modes, etc.
If a callable is returned, it will be assembled into a pool listener that receives the direct DBAPI connection, with all wrappers removed.
If None is returned, no listener will be generated.
-
preparer
¶ alias of
IdentifierPreparer
-
set_isolation_level
(dbapi_conn, level)¶ - inherited from the
set_isolation_level()
method ofDialect
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
Connection
andEngine
isolation level facilities; these APIs should be preferred for most typical use cases.더 보기
Connection.get_isolation_level()
- view current levelConnection.default_isolation_level
- view default levelConnection.execution_options.isolation_level
- set perConnection
isolation levelcreate_engine.isolation_level
- set perEngine
isolation level
-
statement_compiler
¶ alias of
SQLCompiler
-
type_descriptor
(typeobj)¶ Provide a database-specific
TypeEngine
object, given the generic object which comes from the types module.This method looks for a dictionary called
colspecs
as a class or instance-level variable, and passes on totypes.adapt_type()
.
-
-
class
sqlalchemy.engine.interfaces.
Dialect
¶ Define the behavior of a specific database and DB-API combination.
Any aspect of metadata definition, SQL query generation, execution, result-set handling, or anything else which varies between databases is defined under the general category of the Dialect. The Dialect acts as a factory for other database-specific object implementations including ExecutionContext, Compiled, DefaultGenerator, and TypeEngine.
All Dialects implement the following attributes:
- name
- identifying name for the dialect from a DBAPI-neutral point of view (i.e. ‘sqlite’)
- driver
- identifying name for the dialect’s DBAPI
- positional
- True if the paramstyle for this Dialect is positional.
- paramstyle
- the paramstyle to be used (some DB-APIs support multiple paramstyles).
- convert_unicode
- True if Unicode conversion should be applied to all
str
types. - encoding
- type of encoding to use for unicode, usually defaults to ‘utf-8’.
- statement_compiler
- a
Compiled
class used to compile SQL statements - ddl_compiler
- a
Compiled
class used to compile DDL statements - server_version_info
- a tuple containing a version number for the DB backend in use. This value is only available for supporting dialects, and is typically populated during the initial connection to the database.
- default_schema_name
- the name of the default schema. This value is only available for supporting dialects, and is typically populated during the initial connection to the database.
- execution_ctx_cls
- a
ExecutionContext
class used to handle statement execution - execute_sequence_format
- either the ‘tuple’ or ‘list’ type, depending on what cursor.execute() accepts for the second argument (they vary).
- preparer
- a
IdentifierPreparer
class used to quote identifiers. - supports_alter
True
if the database supportsALTER TABLE
.- max_identifier_length
- The maximum length of identifier names.
- supports_unicode_statements
- Indicate whether the DB-API can receive SQL statements as Python unicode strings
- supports_unicode_binds
- Indicate whether the DB-API can receive string bind parameters as Python unicode strings
- supports_sane_rowcount
- Indicate whether the dialect properly implements rowcount for
UPDATE
andDELETE
statements. - supports_sane_multi_rowcount
- Indicate whether the dialect properly implements rowcount for
UPDATE
andDELETE
statements when executed via executemany. - preexecute_autoincrement_sequences
- True if ‘implicit’ primary key functions must be executed separately in order to get their value. This is currently oriented towards Postgresql.
- implicit_returning
- use RETURNING or equivalent during INSERT execution in order to load newly generated primary keys and other column defaults in one execution, which are then available via inserted_primary_key. If an insert statement has returning() specified explicitly, the “implicit” functionality is not used and inserted_primary_key will not be available.
- dbapi_type_map
A mapping of DB-API type objects present in this Dialect’s DB-API implementation mapped to TypeEngine implementations used by the dialect.
This is used to apply types to result sets based on the DB-API types present in cursor.description; it only takes effect for result sets against textual statements where no explicit typemap was present.
- colspecs
- A dictionary of TypeEngine classes from sqlalchemy.types mapped to subclasses that are specific to the dialect class. This dictionary is class-level only and is not accessed from the dialect instance itself.
- supports_default_values
- Indicates if the construct
INSERT INTO tablename DEFAULT VALUES
is supported - supports_sequences
- Indicates if the dialect supports CREATE SEQUENCE or similar.
- sequences_optional
- If True, indicates if the “optional” flag on the Sequence() construct should signal to not generate a CREATE SEQUENCE. Applies only to dialects that support sequences. Currently used only to allow Postgresql SERIAL to be used on a column that specifies Sequence() for usage on other backends.
- supports_native_enum
- Indicates if the dialect supports a native ENUM construct. This will prevent types.Enum from generating a CHECK constraint when that type is used.
- supports_native_boolean
- Indicates if the dialect supports a native boolean construct. This will prevent types.Boolean from generating a CHECK constraint when that type is used.
- dbapi_exception_translation_map
A dictionary of names that will contain as values the names of pep-249 exceptions (“IntegrityError”, “OperationalError”, etc) keyed to alternate class names, to support the case where a DBAPI has exception classes that aren’t named as they are referred to (e.g. IntegrityError = MyException). In the vast majority of cases this dictionary is empty.
버전 1.0.5에 추가.
-
connect
()¶ return a callable which sets up a newly created DBAPI connection.
The callable accepts a single argument “conn” which is the DBAPI connection itself. It has no return value.
This is used to set dialect-wide per-connection options such as isolation modes, unicode modes, etc.
If a callable is returned, it will be assembled into a pool listener that receives the direct DBAPI connection, with all wrappers removed.
If None is returned, no listener will be generated.
-
create_connect_args
(url)¶ Build DB-API compatible connection arguments.
Given a
URL
object, returns a tuple consisting of a *args/**kwargs suitable to send directly to the dbapi’s connect function.
-
create_xid
()¶ Create a two-phase transaction ID.
This id will be passed to do_begin_twophase(), do_rollback_twophase(), do_commit_twophase(). Its format is unspecified.
-
denormalize_name
(name)¶ convert the given name to a case insensitive identifier for the backend if it is an all-lowercase name.
this method is only used if the dialect defines requires_name_normalize=True.
-
do_begin
(dbapi_connection)¶ Provide an implementation of
connection.begin()
, given a DB-API connection.The DBAPI has no dedicated “begin” method and it is expected that transactions are implicit. This hook is provided for those DBAPIs that might need additional help in this area.
Note that
Dialect.do_begin()
is not called unless aTransaction
object is in use. TheDialect.do_autocommit()
hook is provided for DBAPIs that need some extra commands emitted after a commit in order to enter the next transaction, when the SQLAlchemyConnection
is used in its default “autocommit” mode.매개 변수: dbapi_connection¶ – a DBAPI connection, typically proxied within a ConnectionFairy
.
-
do_begin_twophase
(connection, xid)¶ Begin a two phase transaction on the given connection.
매개 변수: - connection¶ – a
Connection
. - xid¶ – xid
- connection¶ – a
-
do_close
(dbapi_connection)¶ Provide an implementation of
connection.close()
, given a DBAPI connection.This hook is called by the
Pool
when a connection has been detached from the pool, or is being returned beyond the normal capacity of the pool.버전 0.8에 추가.
-
do_commit
(dbapi_connection)¶ Provide an implementation of
connection.commit()
, given a DB-API connection.매개 변수: dbapi_connection¶ – a DBAPI connection, typically proxied within a ConnectionFairy
.
-
do_commit_twophase
(connection, xid, is_prepared=True, recover=False)¶ Commit a two phase transaction on the given connection.
매개 변수: - connection¶ – a
Connection
. - xid¶ – xid
- is_prepared¶ – whether or not
TwoPhaseTransaction.prepare()
was called. - recover¶ – if the recover flag was passed.
- connection¶ – a
-
do_execute
(cursor, statement, parameters, context=None)¶ Provide an implementation of
cursor.execute(statement, parameters)
.
-
do_execute_no_params
(cursor, statement, parameters, context=None)¶ Provide an implementation of
cursor.execute(statement)
.The parameter collection should not be sent.
-
do_executemany
(cursor, statement, parameters, context=None)¶ Provide an implementation of
cursor.executemany(statement, parameters)
.
-
do_prepare_twophase
(connection, xid)¶ Prepare a two phase transaction on the given connection.
매개 변수: - connection¶ – a
Connection
. - xid¶ – xid
- connection¶ – a
-
do_recover_twophase
(connection)¶ Recover list of uncommited prepared two phase transaction identifiers on the given connection.
매개 변수: connection¶ – a Connection
.
-
do_release_savepoint
(connection, name)¶ Release the named savepoint on a connection.
매개 변수: - connection¶ – a
Connection
. - name¶ – savepoint name.
- connection¶ – a
-
do_rollback
(dbapi_connection)¶ Provide an implementation of
connection.rollback()
, given a DB-API connection.매개 변수: dbapi_connection¶ – a DBAPI connection, typically proxied within a ConnectionFairy
.
-
do_rollback_to_savepoint
(connection, name)¶ Rollback a connection to the named savepoint.
매개 변수: - connection¶ – a
Connection
. - name¶ – savepoint name.
- connection¶ – a
-
do_rollback_twophase
(connection, xid, is_prepared=True, recover=False)¶ Rollback a two phase transaction on the given connection.
매개 변수: - connection¶ – a
Connection
. - xid¶ – xid
- is_prepared¶ – whether or not
TwoPhaseTransaction.prepare()
was called. - recover¶ – if the recover flag was passed.
- connection¶ – a
-
do_savepoint
(connection, name)¶ Create a savepoint with the given name.
매개 변수: - connection¶ – a
Connection
. - name¶ – savepoint name.
- connection¶ – a
-
classmethod
engine_created
(engine)¶ A convenience hook called before returning the final
Engine
.If the dialect returned a different class from the
get_dialect_cls()
method, then the hook is called on both classes, first on the dialect class returned by theget_dialect_cls()
method and then on the class on which the method was called.The hook should be used by dialects and/or wrappers to apply special events to the engine or its components. In particular, it allows a dialect-wrapping class to apply dialect-level events.
버전 1.0.3에 추가.
-
get_columns
(connection, table_name, schema=None, **kw)¶ Return information about columns in table_name.
Given a
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}
Additional column attributes may be present.
-
classmethod
get_dialect_cls
(url)¶ Given a URL, return the
Dialect
that will be used.This is a hook that allows an external plugin to provide functionality around an existing dialect, by allowing the plugin to be loaded from the url based on an entrypoint, and then the plugin returns the actual dialect to be used.
By default this just returns the cls.
버전 1.0.3에 추가.
-
get_foreign_keys
(connection, table_name, schema=None, **kw)¶ Return information about foreign_keys in table_name.
Given a
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
-
get_indexes
(connection, table_name, schema=None, **kw)¶ Return information about indexes in table_name.
Given a
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
-
get_isolation_level
(dbapi_conn)¶ Given a DBAPI connection, return its isolation level.
When working with a
Connection
object, the corresponding DBAPI connection may be procured using theConnection.connection
accessor.Note that this is a dialect-level method which is used as part of the implementation of the
Connection
andEngine
isolation level facilities; these APIs should be preferred for most typical use cases.더 보기
Connection.get_isolation_level()
- view current levelConnection.default_isolation_level
- view default levelConnection.execution_options.isolation_level
- set perConnection
isolation levelcreate_engine.isolation_level
- set perEngine
isolation level
-
get_pk_constraint
(connection, table_name, schema=None, **kw)¶ Return information about the primary key constraint on table_name`.
Given a
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.
-
get_primary_keys
(connection, table_name, schema=None, **kw)¶ Return information about primary keys in table_name.
Deprecated. This method is only called by the default implementation of
Dialect.get_pk_constraint()
. Dialects should instead implement theDialect.get_pk_constraint()
method directly.
-
get_table_names
(connection, schema=None, **kw)¶ Return a list of table names for schema.
-
get_temp_table_names
(connection, schema=None, **kw)¶ Return a list of temporary table names on the given connection, if supported by the underlying backend.
-
get_temp_view_names
(connection, schema=None, **kw)¶ Return a list of temporary view names on the given connection, if supported by the underlying backend.
-
get_unique_constraints
(connection, table_name, schema=None, **kw)¶ 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.
버전 0.9.0에 추가.
-
get_view_definition
(connection, view_name, schema=None, **kw)¶ Return view definition.
Given a
Connection
, a string view_name, and an optional string schema, return the view definition.
-
get_view_names
(connection, schema=None, **kw)¶ Return a list of all view names available in the database.
- schema:
- Optional, retrieve names from a non-default schema.
-
has_sequence
(connection, sequence_name, schema=None)¶ Check the existence of a particular sequence in the database.
Given a
Connection
object and a string sequence_name, return True if the given sequence exists in the database, False otherwise.
-
has_table
(connection, table_name, schema=None)¶ Check the existence of a particular table in the database.
Given a
Connection
object and a string table_name, return True if the given table (possibly within the specified schema) exists in the database, False otherwise.
-
initialize
(connection)¶ 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().
-
is_disconnect
(e, connection, cursor)¶ Return True if the given DB-API error indicates an invalid connection
-
normalize_name
(name)¶ convert the given name to lowercase if it is detected as case insensitive.
this method is only used if the dialect defines requires_name_normalize=True.
-
reflecttable
(connection, table, include_columns, exclude_columns)¶ Load table description from the database.
Given a
Connection
and aTable
object, reflect its columns and properties from the database.The implementation of this method is provided by
DefaultDialect.reflecttable()
, which makes use ofInspector
to retrieve column information.Dialects should not seek to implement this method, and should instead implement individual schema inspection operations such as
Dialect.get_columns()
,Dialect.get_pk_constraint()
, etc.
-
reset_isolation_level
(dbapi_conn)¶ Given a DBAPI connection, revert its isolation to the default.
Note that this is a dialect-level method which is used as part of the implementation of the
Connection
andEngine
isolation level facilities; these APIs should be preferred for most typical use cases.더 보기
Connection.get_isolation_level()
- view current levelConnection.default_isolation_level
- view default levelConnection.execution_options.isolation_level
- set perConnection
isolation levelcreate_engine.isolation_level
- set perEngine
isolation level
-
set_isolation_level
(dbapi_conn, level)¶ 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
Connection
andEngine
isolation level facilities; these APIs should be preferred for most typical use cases.더 보기
Connection.get_isolation_level()
- view current levelConnection.default_isolation_level
- view default levelConnection.execution_options.isolation_level
- set perConnection
isolation levelcreate_engine.isolation_level
- set perEngine
isolation level
-
classmethod
type_descriptor
(typeobj)¶ Transform a generic type to a dialect-specific type.
Dialect classes will usually use the
types.adapt_type()
function in the types module to accomplish this.The returned result is cached per dialect class so can contain no dialect-instance state.
-
class
sqlalchemy.engine.default.
DefaultExecutionContext
¶ Bases:
sqlalchemy.engine.interfaces.ExecutionContext
-
get_lastrowid
()¶ return self.cursor.lastrowid, or equivalent, after an INSERT.
This may involve calling special cursor functions, issuing a new SELECT on the cursor (or a new one), or returning a stored value that was calculated within post_exec().
This function will only be called for dialects which support “implicit” primary key generation, keep preexecute_autoincrement_sequences set to False, and when no explicit id value was bound to the statement.
The function is called once, directly after post_exec() and before the transaction is committed or ResultProxy is generated. If the post_exec() method assigns a value to self._lastrowid, the value is used in place of calling get_lastrowid().
Note that this method is not equivalent to the
lastrowid
method onResultProxy
, which is a direct proxy to the DBAPIlastrowid
accessor in all cases.
-
get_result_processor
(type_, colname, coltype)¶ Return a ‘result processor’ for a given type as present in cursor.description.
This has a default implementation that dialects can override for context-sensitive result type handling.
-
set_input_sizes
(translate=None, exclude_types=None)¶ Given a cursor and ClauseParameters, call the appropriate style of
setinputsizes()
on the cursor, using DB-API types from the bind parameter’sTypeEngine
objects.This method only called by those dialects which require it, currently cx_oracle.
-
-
class
sqlalchemy.engine.interfaces.
ExecutionContext
¶ A messenger object for a Dialect that corresponds to a single execution.
ExecutionContext should have these data members:
- connection
- Connection object which can be freely used by default value generators to execute SQL. This Connection should reference the same underlying connection/transactional resources of root_connection.
- root_connection
- Connection object which is the source of this ExecutionContext. This Connection may have close_with_result=True set, in which case it can only be used once.
- dialect
- dialect which created this ExecutionContext.
- cursor
- DB-API cursor procured from the connection,
- compiled
- if passed to constructor, sqlalchemy.engine.base.Compiled object being executed,
- statement
- string version of the statement to be executed. Is either passed to the constructor, or must be created from the sql.Compiled object by the time pre_exec() has completed.
- parameters
- bind parameters passed to the execute() method. For compiled statements, this is a dictionary or list of dictionaries. For textual statements, it should be in a format suitable for the dialect’s paramstyle (i.e. dict or list of dicts for non positional, list or list of lists/tuples for positional).
- isinsert
- True if the statement is an INSERT.
- isupdate
- True if the statement is an UPDATE.
- should_autocommit
- True if the statement is a “committable” statement.
- prefetch_cols
- a list of Column objects for which a client-side default was fired off. Applies to inserts and updates.
- postfetch_cols
- a list of Column objects for which a server-side default or inline SQL expression value was fired off. Applies to inserts and updates.
-
create_cursor
()¶ Return a new cursor generated from this ExecutionContext’s connection.
Some dialects may wish to change the behavior of connection.cursor(), such as postgresql which may return a PG “server side” cursor.
-
exception
= None¶ A DBAPI-level exception that was caught when this ExecutionContext attempted to execute a statement.
This attribute is meaningful only within the
ConnectionEvents.dbapi_error()
event.버전 0.9.7에 추가.
-
get_rowcount
()¶ Return the DBAPI
cursor.rowcount
value, or in some cases an interpreted value.See
ResultProxy.rowcount
for details on this.
-
handle_dbapi_exception
(e)¶ Receive a DBAPI exception which occurred upon execute, result fetch, etc.
-
is_disconnect
= None¶ Boolean flag set to True or False when a DBAPI-level exception is caught when this ExecutionContext attempted to execute a statement.
This attribute is meaningful only within the
ConnectionEvents.dbapi_error()
event.버전 0.9.7에 추가.
-
lastrow_has_defaults
()¶ Return True if the last INSERT or UPDATE row contained inlined or database-side defaults.
-
post_exec
()¶ Called after the execution of a compiled statement.
If a compiled statement was passed to this ExecutionContext, the last_insert_ids, last_inserted_params, etc. datamembers should be available after this method completes.
-
pre_exec
()¶ Called before an execution of a compiled statement.
If a compiled statement was passed to this ExecutionContext, the statement and parameters datamembers must be initialized after this statement is complete.
-
result
()¶ Return a result object corresponding to this ExecutionContext.
Returns a ResultProxy.
-
should_autocommit_text
(statement)¶ Parse the given textual statement and return True if it refers to a “committable” statement
-
class
sqlalchemy.log.
Identified
¶
-
class
sqlalchemy.sql.compiler.
IdentifierPreparer
(dialect, initial_quote='"', final_quote=None, escape_quote='"', omit_schema=False)¶ Handle quoting and case-folding of identifiers based on options.
-
__init__
(dialect, initial_quote='"', final_quote=None, escape_quote='"', omit_schema=False)¶ Construct a new
IdentifierPreparer
object.- initial_quote
- Character that begins a delimited identifier.
- final_quote
- Character that ends a delimited identifier. Defaults to initial_quote.
- omit_schema
- Prevent prepending schema name. Useful for databases that do not support schemae.
-
format_column
(column, use_table=False, name=None, table_name=None)¶ Prepare a quoted column name.
-
format_schema
(name, quote=None)¶ Prepare a quoted schema name.
-
format_table
(table, use_schema=True, name=None)¶ Prepare a quoted table and schema name.
-
format_table_seq
(table, use_schema=True)¶ Format table name and schema as a tuple.
-
quote
(ident, force=None)¶ Conditionally quote an identifier.
the ‘force’ flag should be considered deprecated.
-
quote_identifier
(value)¶ Quote an identifier.
Subclasses should override this to provide database-dependent quoting behavior.
-
quote_schema
(schema, force=None)¶ Conditionally quote a schema.
Subclasses can override this to provide database-dependent quoting behavior for schema names.
the ‘force’ flag should be considered deprecated.
-
unformat_identifiers
(identifiers)¶ Unpack ‘schema.table.column’-like strings into components.
-
-
class
sqlalchemy.sql.compiler.
SQLCompiler
(dialect, statement, column_keys=None, inline=False, **kwargs)¶ Bases:
sqlalchemy.sql.compiler.Compiled
Default implementation of
Compiled
.Compiles
ClauseElement
objects into SQL strings.-
__init__
(dialect, statement, column_keys=None, inline=False, **kwargs)¶ Construct a new
SQLCompiler
object.매개 변수: - dialect¶ –
Dialect
to be used - statement¶ –
ClauseElement
to be compiled - column_keys¶ – a list of column names to be compiled into an INSERT or UPDATE statement.
- inline¶ – whether to generate INSERT statements as “inline”, e.g. not formatted to return any generated defaults
- kwargs¶ – additional keyword arguments to be consumed by the superclass.
- dialect¶ –
-
ansi_bind_rules
= False¶ SQL 92 doesn’t allow bind parameters to be used in the columns clause of a SELECT, nor does it allow ambiguous expressions like ”? = ?”. A compiler subclass can set this flag to False if the target driver/DB enforces this
-
construct_params
(params=None, _group_number=None, _check=True)¶ return a dictionary of bind parameter keys and values
-
default_from
()¶ Called when a SELECT statement has no froms, and no FROM clause is to be appended.
Gives Oracle a chance to tack on a
FROM DUAL
to the string output.
-
escape_literal_column
(text)¶ provide escaping for the literal_column() construct.
-
get_select_precolumns
(select, **kw)¶ Called when building a
SELECT
statement, position is just before column list.
-
isdelete
= False¶ class-level defaults which can be set at the instance level to define if this Compiled instance represents INSERT/UPDATE/DELETE
-
isinsert
= False¶ class-level defaults which can be set at the instance level to define if this Compiled instance represents INSERT/UPDATE/DELETE
-
isupdate
= False¶ class-level defaults which can be set at the instance level to define if this Compiled instance represents INSERT/UPDATE/DELETE
-
params
¶ Return the bind param dictionary embedded into this compiled object, for those values that are present.
-
render_literal_value
(value, type_)¶ Render the value of a bind parameter as a quoted literal.
This is used for statement sections that do not accept bind parameters on the target driver/database.
This should be implemented by subclasses using the quoting services of the DBAPI.
-
render_table_with_column_in_update_from
= False¶ set to True classwide to indicate the SET clause in a multi-table UPDATE statement should qualify columns with the table name (i.e. MySQL only)
-
returning
= None¶ holds the “returning” collection of columns if the statement is CRUD and defines returning columns either implicitly or explicitly
-
returning_precedes_values
= False¶ set to True classwide to generate RETURNING clauses before the VALUES or WHERE clause (i.e. MSSQL)
-
update_from_clause
(update_stmt, from_table, extra_froms, from_hints, **kw)¶ Provide a hook to override the generation of an UPDATE..FROM clause.
MySQL and MSSQL override this.
-
update_limit_clause
(update_stmt)¶ Provide a hook for MySQL to add LIMIT to the UPDATE
-
update_tables_clause
(update_stmt, from_table, extra_froms, **kw)¶ Provide a hook to override the initial table clause in an UPDATE statement.
MySQL overrides this.
-