Insert, Updates, Deletes¶
INSERT, UPDATE and DELETE statements build on a hierarchy starting
with UpdateBase
. The Insert
and Update
constructs build on the intermediary ValuesBase
.
DML Foundational Constructors¶
Top level “INSERT”, “UPDATE”, “DELETE” constructors.
Object Name | Description |
---|---|
delete(table) |
Construct |
insert(table) |
Construct an |
update(table) |
Construct an |
- function sqlalchemy.sql.expression.delete(table: _DMLTableArgument) Delete ¶
Construct
Delete
object.E.g.:
from sqlalchemy import delete stmt = ( delete(user_table). where(user_table.c.id == 5) )
Similar functionality is available via the
TableClause.delete()
method onTable
.- Parameters:
table – The table to delete rows from.
See also
Using UPDATE and DELETE Statements - in the SQLAlchemy Unified Tutorial
- function sqlalchemy.sql.expression.insert(table: _DMLTableArgument) Insert ¶
Construct an
Insert
object.E.g.:
from sqlalchemy import insert stmt = ( insert(user_table). values(name='username', fullname='Full Username') )
Similar functionality is available via the
TableClause.insert()
method onTable
.See also
Using INSERT Statements - in the SQLAlchemy Unified Tutorial
- Parameters:
table –
TableClause
which is the subject of the insert.values – collection of values to be inserted; see
Insert.values()
for a description of allowed formats here. Can be omitted entirely; aInsert
construct will also dynamically render the VALUES clause at execution time based on the parameters passed toConnection.execute()
.inline – if True, no attempt will be made to retrieve the SQL-generated default values to be provided within the statement; in particular, this allows SQL expressions to be rendered ‘inline’ within the statement without the need to pre-execute them beforehand; for backends that support “returning”, this turns off the “implicit returning” feature for the statement.
If both
insert.values
and compile-time bind parameters are present, the compile-time bind parameters override the information specified withininsert.values
on a per-key basis.The keys within
Insert.values
can be eitherColumn
objects or their string identifiers. Each key may reference one of:a literal data value (i.e. string, number, etc.);
a Column object;
a SELECT statement.
If a
SELECT
statement is specified which references thisINSERT
statement’s table, the statement will be correlated against theINSERT
statement.See also
Using INSERT Statements - in the SQLAlchemy Unified Tutorial
- function sqlalchemy.sql.expression.update(table: _DMLTableArgument) Update ¶
Construct an
Update
object.E.g.:
from sqlalchemy import update stmt = ( update(user_table). where(user_table.c.id == 5). values(name='user #5') )
Similar functionality is available via the
TableClause.update()
method onTable
.- Parameters:
table – A
Table
object representing the database table to be updated.
See also
Using UPDATE and DELETE Statements - in the SQLAlchemy Unified Tutorial
DML Class Documentation Constructors¶
Class documentation for the constructors listed at DML Foundational Constructors.
Object Name | Description |
---|---|
Represent a DELETE construct. |
|
Represent an INSERT construct. |
|
Represent an Update construct. |
|
Form the base for |
|
Supplies support for |
- class sqlalchemy.sql.expression.Delete¶
Represent a DELETE construct.
The
Delete
object is created using thedelete()
function.Members
Class signature
class
sqlalchemy.sql.expression.Delete
(sqlalchemy.sql.expression.DMLWhereBase
,sqlalchemy.sql.expression.UpdateBase
)-
method
sqlalchemy.sql.expression.Delete.
where(*whereclause: _ColumnExpressionArgument[bool]) Self ¶ inherited from the
DMLWhereBase.where()
method ofDMLWhereBase
Return a new construct with the given expression(s) added to its WHERE clause, joined to the existing clause via AND, if any.
Both
Update.where()
andDelete.where()
support multiple-table forms, including database-specificUPDATE...FROM
as well asDELETE..USING
. For backends that don’t have multiple-table support, a backend agnostic approach to using multiple tables is to make use of correlated subqueries. See the linked tutorial sections below for examples.
-
method
sqlalchemy.sql.expression.Delete.
returning(*cols: _ColumnsClauseArgument[Any], sort_by_parameter_order: bool = False, **_UpdateBase__kw: Any) UpdateBase ¶ inherited from the
UpdateBase.returning()
method ofUpdateBase
Add a RETURNING or equivalent clause to this statement.
e.g.:
>>> stmt = ( ... table.update() ... .where(table.c.data == "value") ... .values(status="X") ... .returning(table.c.server_flag, table.c.updated_timestamp) ... ) >>> print(stmt) {printsql}UPDATE some_table SET status=:status WHERE some_table.data = :data_1 RETURNING some_table.server_flag, some_table.updated_timestamp
The method may be invoked multiple times to add new entries to the list of expressions to be returned.
New in version 1.4.0b2: The method may be invoked multiple times to add new entries to the list of expressions to be returned.
The given collection of column expressions should be derived from the table that is the target of the INSERT, UPDATE, or DELETE. While
Column
objects are typical, the elements can also be expressions:>>> stmt = table.insert().returning( ... (table.c.first_name + " " + table.c.last_name).label("fullname") ... ) >>> print(stmt) {printsql}INSERT INTO some_table (first_name, last_name) VALUES (:first_name, :last_name) RETURNING some_table.first_name || :first_name_1 || some_table.last_name AS fullname
Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.
Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using
CursorResult.fetchone()
and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.
- Parameters:
*cols – series of columns, SQL expressions, or whole tables entities to be returned.
sort_by_parameter_order –
for a batch INSERT that is being executed against multiple parameter sets, organize the results of RETURNING so that the returned rows correspond to the order of parameter sets passed in. This applies only to an executemany execution for supporting dialects and typically makes use of the insertmanyvalues feature.
New in version 2.0.10.
See also
Correlating RETURNING rows to parameter sets - background on sorting of RETURNING rows for bulk INSERT (Core level discussion)
Correlating RETURNING records with input data order - example of use with ORM Bulk INSERT Statements (ORM level discussion)
See also
UpdateBase.return_defaults()
- an alternative method tailored towards efficient fetching of server-side defaults and triggers for single-row INSERTs or UPDATEs.
-
method
- class sqlalchemy.sql.expression.Insert¶
Represent an INSERT construct.
The
Insert
object is created using theinsert()
function.Members
Class signature
class
sqlalchemy.sql.expression.Insert
(sqlalchemy.sql.expression.ValuesBase
)-
method
sqlalchemy.sql.expression.Insert.
values(*args: Union[_DMLColumnKeyMapping[Any], Sequence[Any]], **kwargs: Any) Self ¶ inherited from the
ValuesBase.values()
method ofValuesBase
Specify a fixed VALUES clause for an INSERT statement, or the SET clause for an UPDATE.
Note that the
Insert
andUpdate
constructs support per-execution time formatting of the VALUES and/or SET clauses, based on the arguments passed toConnection.execute()
. However, theValuesBase.values()
method can be used to “fix” a particular set of parameters into the statement.Multiple calls to
ValuesBase.values()
will produce a new construct, each one with the parameter list modified to include the new parameters sent. In the typical case of a single dictionary of parameters, the newly passed keys will replace the same keys in the previous construct. In the case of a list-based “multiple values” construct, each new list of values is extended onto the existing list of values.- Parameters:
**kwargs –
key value pairs representing the string key of a
Column
mapped to the value to be rendered into the VALUES or SET clause:users.insert().values(name="some name") users.update().where(users.c.id==5).values(name="some name")
*args –
As an alternative to passing key/value parameters, a dictionary, tuple, or list of dictionaries or tuples can be passed as a single positional argument in order to form the VALUES or SET clause of the statement. The forms that are accepted vary based on whether this is an
Insert
or anUpdate
construct.For either an
Insert
orUpdate
construct, a single dictionary can be passed, which works the same as that of the kwargs form:users.insert().values({"name": "some name"}) users.update().values({"name": "some new name"})
Also for either form but more typically for the
Insert
construct, a tuple that contains an entry for every column in the table is also accepted:users.insert().values((5, "some name"))
The
Insert
construct also supports being passed a list of dictionaries or full-table-tuples, which on the server will render the less common SQL syntax of “multiple values” - this syntax is supported on backends such as SQLite, PostgreSQL, MySQL, but not necessarily others:users.insert().values([ {"name": "some name"}, {"name": "some other name"}, {"name": "yet another name"}, ])
The above form would render a multiple VALUES statement similar to:
INSERT INTO users (name) VALUES (:name_1), (:name_2), (:name_3)
It is essential to note that passing multiple values is NOT the same as using traditional executemany() form. The above syntax is a special syntax not typically used. To emit an INSERT statement against multiple rows, the normal method is to pass a multiple values list to the
Connection.execute()
method, which is supported by all database backends and is generally more efficient for a very large number of parameters.See also
Sending Multiple Parameters - an introduction to the traditional Core method of multiple parameter set invocation for INSERTs and other statements.
The UPDATE construct also supports rendering the SET parameters in a specific order. For this feature refer to the
Update.ordered_values()
method.See also
-
method
sqlalchemy.sql.expression.Insert.
returning(*cols: _ColumnsClauseArgument[Any], sort_by_parameter_order: bool = False, **_UpdateBase__kw: Any) UpdateBase ¶ inherited from the
UpdateBase.returning()
method ofUpdateBase
Add a RETURNING or equivalent clause to this statement.
e.g.:
>>> stmt = ( ... table.update() ... .where(table.c.data == "value") ... .values(status="X") ... .returning(table.c.server_flag, table.c.updated_timestamp) ... ) >>> print(stmt) {printsql}UPDATE some_table SET status=:status WHERE some_table.data = :data_1 RETURNING some_table.server_flag, some_table.updated_timestamp
The method may be invoked multiple times to add new entries to the list of expressions to be returned.
New in version 1.4.0b2: The method may be invoked multiple times to add new entries to the list of expressions to be returned.
The given collection of column expressions should be derived from the table that is the target of the INSERT, UPDATE, or DELETE. While
Column
objects are typical, the elements can also be expressions:>>> stmt = table.insert().returning( ... (table.c.first_name + " " + table.c.last_name).label("fullname") ... ) >>> print(stmt) {printsql}INSERT INTO some_table (first_name, last_name) VALUES (:first_name, :last_name) RETURNING some_table.first_name || :first_name_1 || some_table.last_name AS fullname
Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.
Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using
CursorResult.fetchone()
and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.
- Parameters:
*cols – series of columns, SQL expressions, or whole tables entities to be returned.
sort_by_parameter_order –
for a batch INSERT that is being executed against multiple parameter sets, organize the results of RETURNING so that the returned rows correspond to the order of parameter sets passed in. This applies only to an executemany execution for supporting dialects and typically makes use of the insertmanyvalues feature.
New in version 2.0.10.
See also
Correlating RETURNING rows to parameter sets - background on sorting of RETURNING rows for bulk INSERT (Core level discussion)
Correlating RETURNING records with input data order - example of use with ORM Bulk INSERT Statements (ORM level discussion)
See also
UpdateBase.return_defaults()
- an alternative method tailored towards efficient fetching of server-side defaults and triggers for single-row INSERTs or UPDATEs.
-
method
sqlalchemy.sql.expression.Insert.
from_select(names: Sequence[_DMLColumnArgument], select: Selectable, include_defaults: bool = True) Self ¶ Return a new
Insert
construct which represents anINSERT...FROM SELECT
statement.e.g.:
sel = select(table1.c.a, table1.c.b).where(table1.c.c > 5) ins = table2.insert().from_select(['a', 'b'], sel)
- Parameters:
names – a sequence of string column names or
Column
objects representing the target columns.select – a
select()
construct,FromClause
or other construct which resolves into aFromClause
, such as an ORMQuery
object, etc. The order of columns returned from this FROM clause should correspond to the order of columns sent as thenames
parameter; while this is not checked before passing along to the database, the database would normally raise an exception if these column lists don’t correspond.include_defaults –
if True, non-server default values and SQL expressions as specified on
Column
objects (as documented in Column INSERT/UPDATE Defaults) not otherwise specified in the list of names will be rendered into the INSERT and SELECT statements, so that these values are also included in the data to be inserted.Note
A Python-side default that uses a Python callable function will only be invoked once for the whole statement, and not per row.
-
method
sqlalchemy.sql.expression.Insert.
inline() Self ¶ Make this
Insert
construct “inline” .When set, no attempt will be made to retrieve the SQL-generated default values to be provided within the statement; in particular, this allows SQL expressions to be rendered ‘inline’ within the statement without the need to pre-execute them beforehand; for backends that support “returning”, this turns off the “implicit returning” feature for the statement.
Changed in version 1.4: the
Insert.inline
parameter is now superseded by theInsert.inline()
method.
-
attribute
sqlalchemy.sql.expression.Insert.
select: Optional[Select[Any]] = None¶ SELECT statement for INSERT .. FROM SELECT
-
method
- class sqlalchemy.sql.expression.Update¶
Represent an Update construct.
The
Update
object is created using theupdate()
function.Members
Class signature
class
sqlalchemy.sql.expression.Update
(sqlalchemy.sql.expression.DMLWhereBase
,sqlalchemy.sql.expression.ValuesBase
)-
method
sqlalchemy.sql.expression.Update.
returning(*cols: _ColumnsClauseArgument[Any], sort_by_parameter_order: bool = False, **_UpdateBase__kw: Any) UpdateBase ¶ inherited from the
UpdateBase.returning()
method ofUpdateBase
Add a RETURNING or equivalent clause to this statement.
e.g.:
>>> stmt = ( ... table.update() ... .where(table.c.data == "value") ... .values(status="X") ... .returning(table.c.server_flag, table.c.updated_timestamp) ... ) >>> print(stmt) {printsql}UPDATE some_table SET status=:status WHERE some_table.data = :data_1 RETURNING some_table.server_flag, some_table.updated_timestamp
The method may be invoked multiple times to add new entries to the list of expressions to be returned.
New in version 1.4.0b2: The method may be invoked multiple times to add new entries to the list of expressions to be returned.
The given collection of column expressions should be derived from the table that is the target of the INSERT, UPDATE, or DELETE. While
Column
objects are typical, the elements can also be expressions:>>> stmt = table.insert().returning( ... (table.c.first_name + " " + table.c.last_name).label("fullname") ... ) >>> print(stmt) {printsql}INSERT INTO some_table (first_name, last_name) VALUES (:first_name, :last_name) RETURNING some_table.first_name || :first_name_1 || some_table.last_name AS fullname
Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.
Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using
CursorResult.fetchone()
and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.
- Parameters:
*cols – series of columns, SQL expressions, or whole tables entities to be returned.
sort_by_parameter_order –
for a batch INSERT that is being executed against multiple parameter sets, organize the results of RETURNING so that the returned rows correspond to the order of parameter sets passed in. This applies only to an executemany execution for supporting dialects and typically makes use of the insertmanyvalues feature.
New in version 2.0.10.
See also
Correlating RETURNING rows to parameter sets - background on sorting of RETURNING rows for bulk INSERT (Core level discussion)
Correlating RETURNING records with input data order - example of use with ORM Bulk INSERT Statements (ORM level discussion)
See also
UpdateBase.return_defaults()
- an alternative method tailored towards efficient fetching of server-side defaults and triggers for single-row INSERTs or UPDATEs.
-
method
sqlalchemy.sql.expression.Update.
where(*whereclause: _ColumnExpressionArgument[bool]) Self ¶ inherited from the
DMLWhereBase.where()
method ofDMLWhereBase
Return a new construct with the given expression(s) added to its WHERE clause, joined to the existing clause via AND, if any.
Both
Update.where()
andDelete.where()
support multiple-table forms, including database-specificUPDATE...FROM
as well asDELETE..USING
. For backends that don’t have multiple-table support, a backend agnostic approach to using multiple tables is to make use of correlated subqueries. See the linked tutorial sections below for examples.
-
method
sqlalchemy.sql.expression.Update.
values(*args: Union[_DMLColumnKeyMapping[Any], Sequence[Any]], **kwargs: Any) Self ¶ inherited from the
ValuesBase.values()
method ofValuesBase
Specify a fixed VALUES clause for an INSERT statement, or the SET clause for an UPDATE.
Note that the
Insert
andUpdate
constructs support per-execution time formatting of the VALUES and/or SET clauses, based on the arguments passed toConnection.execute()
. However, theValuesBase.values()
method can be used to “fix” a particular set of parameters into the statement.Multiple calls to
ValuesBase.values()
will produce a new construct, each one with the parameter list modified to include the new parameters sent. In the typical case of a single dictionary of parameters, the newly passed keys will replace the same keys in the previous construct. In the case of a list-based “multiple values” construct, each new list of values is extended onto the existing list of values.- Parameters:
**kwargs –
key value pairs representing the string key of a
Column
mapped to the value to be rendered into the VALUES or SET clause:users.insert().values(name="some name") users.update().where(users.c.id==5).values(name="some name")
*args –
As an alternative to passing key/value parameters, a dictionary, tuple, or list of dictionaries or tuples can be passed as a single positional argument in order to form the VALUES or SET clause of the statement. The forms that are accepted vary based on whether this is an
Insert
or anUpdate
construct.For either an
Insert
orUpdate
construct, a single dictionary can be passed, which works the same as that of the kwargs form:users.insert().values({"name": "some name"}) users.update().values({"name": "some new name"})
Also for either form but more typically for the
Insert
construct, a tuple that contains an entry for every column in the table is also accepted:users.insert().values((5, "some name"))
The
Insert
construct also supports being passed a list of dictionaries or full-table-tuples, which on the server will render the less common SQL syntax of “multiple values” - this syntax is supported on backends such as SQLite, PostgreSQL, MySQL, but not necessarily others:users.insert().values([ {"name": "some name"}, {"name": "some other name"}, {"name": "yet another name"}, ])
The above form would render a multiple VALUES statement similar to:
INSERT INTO users (name) VALUES (:name_1), (:name_2), (:name_3)
It is essential to note that passing multiple values is NOT the same as using traditional executemany() form. The above syntax is a special syntax not typically used. To emit an INSERT statement against multiple rows, the normal method is to pass a multiple values list to the
Connection.execute()
method, which is supported by all database backends and is generally more efficient for a very large number of parameters.See also
Sending Multiple Parameters - an introduction to the traditional Core method of multiple parameter set invocation for INSERTs and other statements.
The UPDATE construct also supports rendering the SET parameters in a specific order. For this feature refer to the
Update.ordered_values()
method.See also
-
method
sqlalchemy.sql.expression.Update.
inline() Self ¶ Make this
Update
construct “inline” .When set, SQL defaults present on
Column
objects via thedefault
keyword will be compiled ‘inline’ into the statement and not pre-executed. This means that their values will not be available in the dictionary returned fromCursorResult.last_updated_params()
.Changed in version 1.4: the
update.inline
parameter is now superseded by theUpdate.inline()
method.
-
method
sqlalchemy.sql.expression.Update.
ordered_values(*args: Tuple[_DMLColumnArgument, Any]) Self ¶ Specify the VALUES clause of this UPDATE statement with an explicit parameter ordering that will be maintained in the SET clause of the resulting UPDATE statement.
E.g.:
stmt = table.update().ordered_values( ("name", "ed"), ("ident": "foo") )
See also
Parameter Ordered Updates - full example of the
Update.ordered_values()
method.Changed in version 1.4: The
Update.ordered_values()
method supersedes theupdate.preserve_parameter_order
parameter, which will be removed in SQLAlchemy 2.0.
-
method
- class sqlalchemy.sql.expression.UpdateBase¶
Form the base for
INSERT
,UPDATE
, andDELETE
statements.Members
entity_description, exported_columns, params(), return_defaults(), returning(), returning_column_descriptions, with_dialect_options(), with_hint()
Class signature
class
sqlalchemy.sql.expression.UpdateBase
(sqlalchemy.sql.roles.DMLRole
,sqlalchemy.sql.expression.HasCTE
,sqlalchemy.sql.expression.HasCompileState
,sqlalchemy.sql.base.DialectKWArgs
,sqlalchemy.sql.expression.HasPrefixes
,sqlalchemy.sql.expression.Generative
,sqlalchemy.sql.expression.ExecutableReturnsRows
,sqlalchemy.sql.expression.ClauseElement
)-
attribute
sqlalchemy.sql.expression.UpdateBase.
entity_description¶ Return a plugin-enabled description of the table and/or entity which this DML construct is operating against.
This attribute is generally useful when using the ORM, as an extended structure which includes information about mapped entities is returned. The section Inspecting entities and columns from ORM-enabled SELECT and DML statements contains more background.
For a Core statement, the structure returned by this accessor is derived from the
UpdateBase.table
attribute, and refers to theTable
being inserted, updated, or deleted:>>> stmt = insert(user_table) >>> stmt.entity_description { "name": "user_table", "table": Table("user_table", ...) }
New in version 1.4.33.
See also
UpdateBase.returning_column_descriptions
Select.column_descriptions
- entity information for aselect()
constructInspecting entities and columns from ORM-enabled SELECT and DML statements - ORM background
-
attribute
sqlalchemy.sql.expression.UpdateBase.
exported_columns¶ Return the RETURNING columns as a column collection for this statement.
New in version 1.4.
-
method
sqlalchemy.sql.expression.UpdateBase.
params(*arg: Any, **kw: Any) NoReturn ¶ Set the parameters for the statement.
This method raises
NotImplementedError
on the base class, and is overridden byValuesBase
to provide the SET/VALUES clause of UPDATE and INSERT.
-
method
sqlalchemy.sql.expression.UpdateBase.
return_defaults(*cols: _DMLColumnArgument, supplemental_cols: Optional[Iterable[_DMLColumnArgument]] = None, sort_by_parameter_order: bool = False) Self ¶ Make use of a RETURNING clause for the purpose of fetching server-side expressions and defaults, for supporting backends only.
Deep Alchemy
The
UpdateBase.return_defaults()
method is used by the ORM for its internal work in fetching newly generated primary key and server default values, in particular to provide the underyling implementation of theMapper.eager_defaults
ORM feature as well as to allow RETURNING support with bulk ORM inserts. Its behavior is fairly idiosyncratic and is not really intended for general use. End users should stick with usingUpdateBase.returning()
in order to add RETURNING clauses to their INSERT, UPDATE and DELETE statements.Normally, a single row INSERT statement will automatically populate the
CursorResult.inserted_primary_key
attribute when executed, which stores the primary key of the row that was just inserted in the form of aRow
object with column names as named tuple keys (and theRow._mapping
view fully populated as well). The dialect in use chooses the strategy to use in order to populate this data; if it was generated using server-side defaults and / or SQL expressions, dialect-specific approaches such ascursor.lastrowid
orRETURNING
are typically used to acquire the new primary key value.However, when the statement is modified by calling
UpdateBase.return_defaults()
before executing the statement, additional behaviors take place only for backends that support RETURNING and forTable
objects that maintain theTable.implicit_returning
parameter at its default value ofTrue
. In these cases, when theCursorResult
is returned from the statement’s execution, not only willCursorResult.inserted_primary_key
be populated as always, theCursorResult.returned_defaults
attribute will also be populated with aRow
named-tuple representing the full range of server generated values from that single row, including values for any columns that specifyColumn.server_default
or which make use ofColumn.default
using a SQL expression.When invoking INSERT statements with multiple rows using insertmanyvalues, the
UpdateBase.return_defaults()
modifier will have the effect of theCursorResult.inserted_primary_key_rows
andCursorResult.returned_defaults_rows
attributes being fully populated with lists ofRow
objects representing newly inserted primary key values as well as newly inserted server generated values for each row inserted. TheCursorResult.inserted_primary_key
andCursorResult.returned_defaults
attributes will also continue to be populated with the first row of these two collections.If the backend does not support RETURNING or the
Table
in use has disabledTable.implicit_returning
, then no RETURNING clause is added and no additional data is fetched, however the INSERT, UPDATE or DELETE statement proceeds normally.E.g.:
stmt = table.insert().values(data='newdata').return_defaults() result = connection.execute(stmt) server_created_at = result.returned_defaults['created_at']
When used against an UPDATE statement
UpdateBase.return_defaults()
instead looks for columns that includeColumn.onupdate
orColumn.server_onupdate
parameters assigned, when constructing the columns that will be included in the RETURNING clause by default if explicit columns were not specified. When used against a DELETE statement, no columns are included in RETURNING by default, they instead must be specified explicitly as there are no columns that normally change values when a DELETE statement proceeds.New in version 2.0:
UpdateBase.return_defaults()
is supported for DELETE statements also and has been moved fromValuesBase
toUpdateBase
.The
UpdateBase.return_defaults()
method is mutually exclusive against theUpdateBase.returning()
method and errors will be raised during the SQL compilation process if both are used at the same time on one statement. The RETURNING clause of the INSERT, UPDATE or DELETE statement is therefore controlled by only one of these methods at a time.The
UpdateBase.return_defaults()
method differs fromUpdateBase.returning()
in these ways:UpdateBase.return_defaults()
method causes theCursorResult.returned_defaults
collection to be populated with the first row from the RETURNING result. This attribute is not populated when usingUpdateBase.returning()
.UpdateBase.return_defaults()
is compatible with existing logic used to fetch auto-generated primary key values that are then populated into theCursorResult.inserted_primary_key
attribute. By contrast, usingUpdateBase.returning()
will have the effect of theCursorResult.inserted_primary_key
attribute being left unpopulated.UpdateBase.return_defaults()
can be called against any backend. Backends that don’t support RETURNING will skip the usage of the feature, rather than raising an exception. The return value ofCursorResult.returned_defaults
will beNone
for backends that don’t support RETURNING or for which the targetTable
setsTable.implicit_returning
toFalse
.An INSERT statement invoked with executemany() is supported if the backend database driver supports the insertmanyvalues feature which is now supported by most SQLAlchemy-included backends. When executemany is used, the
CursorResult.returned_defaults_rows
andCursorResult.inserted_primary_key_rows
accessors will return the inserted defaults and primary keys.New in version 1.4: Added
CursorResult.returned_defaults_rows
andCursorResult.inserted_primary_key_rows
accessors. In version 2.0, the underlying implementation which fetches and populates the data for these attributes was generalized to be supported by most backends, whereas in 1.4 they were only supported by thepsycopg2
driver.
- Parameters:
cols – optional list of column key names or
Column
that acts as a filter for those columns that will be fetched.supplemental_cols –
optional list of RETURNING expressions, in the same form as one would pass to the
UpdateBase.returning()
method. When present, the additional columns will be included in the RETURNING clause, and theCursorResult
object will be “rewound” when returned, so that methods likeCursorResult.all()
will return new rows mostly as though the statement usedUpdateBase.returning()
directly. However, unlike when usingUpdateBase.returning()
directly, the order of the columns is undefined, so can only be targeted using names orRow._mapping
keys; they cannot reliably be targeted positionally.New in version 2.0.
sort_by_parameter_order –
for a batch INSERT that is being executed against multiple parameter sets, organize the results of RETURNING so that the returned rows correspond to the order of parameter sets passed in. This applies only to an executemany execution for supporting dialects and typically makes use of the insertmanyvalues feature.
New in version 2.0.10.
See also
Correlating RETURNING rows to parameter sets - background on sorting of RETURNING rows for bulk INSERT
-
method
sqlalchemy.sql.expression.UpdateBase.
returning(*cols: _ColumnsClauseArgument[Any], sort_by_parameter_order: bool = False, **_UpdateBase__kw: Any) UpdateBase ¶ Add a RETURNING or equivalent clause to this statement.
e.g.:
>>> stmt = ( ... table.update() ... .where(table.c.data == "value") ... .values(status="X") ... .returning(table.c.server_flag, table.c.updated_timestamp) ... ) >>> print(stmt) {printsql}UPDATE some_table SET status=:status WHERE some_table.data = :data_1 RETURNING some_table.server_flag, some_table.updated_timestamp
The method may be invoked multiple times to add new entries to the list of expressions to be returned.
New in version 1.4.0b2: The method may be invoked multiple times to add new entries to the list of expressions to be returned.
The given collection of column expressions should be derived from the table that is the target of the INSERT, UPDATE, or DELETE. While
Column
objects are typical, the elements can also be expressions:>>> stmt = table.insert().returning( ... (table.c.first_name + " " + table.c.last_name).label("fullname") ... ) >>> print(stmt) {printsql}INSERT INTO some_table (first_name, last_name) VALUES (:first_name, :last_name) RETURNING some_table.first_name || :first_name_1 || some_table.last_name AS fullname
Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.
Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using
CursorResult.fetchone()
and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.
- Parameters:
*cols – series of columns, SQL expressions, or whole tables entities to be returned.
sort_by_parameter_order –
for a batch INSERT that is being executed against multiple parameter sets, organize the results of RETURNING so that the returned rows correspond to the order of parameter sets passed in. This applies only to an executemany execution for supporting dialects and typically makes use of the insertmanyvalues feature.
New in version 2.0.10.
See also
Correlating RETURNING rows to parameter sets - background on sorting of RETURNING rows for bulk INSERT (Core level discussion)
Correlating RETURNING records with input data order - example of use with ORM Bulk INSERT Statements (ORM level discussion)
See also
UpdateBase.return_defaults()
- an alternative method tailored towards efficient fetching of server-side defaults and triggers for single-row INSERTs or UPDATEs.
-
attribute
sqlalchemy.sql.expression.UpdateBase.
returning_column_descriptions¶ Return a plugin-enabled description of the columns which this DML construct is RETURNING against, in other words the expressions established as part of
UpdateBase.returning()
.This attribute is generally useful when using the ORM, as an extended structure which includes information about mapped entities is returned. The section Inspecting entities and columns from ORM-enabled SELECT and DML statements contains more background.
For a Core statement, the structure returned by this accessor is derived from the same objects that are returned by the
UpdateBase.exported_columns
accessor:>>> stmt = insert(user_table).returning(user_table.c.id, user_table.c.name) >>> stmt.entity_description [ { "name": "id", "type": Integer, "expr": Column("id", Integer(), table=<user>, ...) }, { "name": "name", "type": String(), "expr": Column("name", String(), table=<user>, ...) }, ]
New in version 1.4.33.
See also
Select.column_descriptions
- entity information for aselect()
constructInspecting entities and columns from ORM-enabled SELECT and DML statements - ORM background
-
method
sqlalchemy.sql.expression.UpdateBase.
with_dialect_options(**opt: Any) Self ¶ Add dialect options to this INSERT/UPDATE/DELETE object.
e.g.:
upd = table.update().dialect_options(mysql_limit=10)
-
method
sqlalchemy.sql.expression.UpdateBase.
with_hint(text: str, selectable: Optional[_DMLTableArgument] = None, dialect_name: str = '*') Self ¶ Add a table hint for a single table to this INSERT/UPDATE/DELETE statement.
Note
UpdateBase.with_hint()
currently applies only to Microsoft SQL Server. For MySQL INSERT/UPDATE/DELETE hints, useUpdateBase.prefix_with()
.The text of the hint is rendered in the appropriate location for the database backend in use, relative to the
Table
that is the subject of this statement, or optionally to that of the givenTable
passed as theselectable
argument.The
dialect_name
option will limit the rendering of a particular hint to a particular backend. Such as, to add a hint that only takes effect for SQL Server:mytable.insert().with_hint("WITH (PAGLOCK)", dialect_name="mssql")
- Parameters:
text – Text of the hint.
selectable – optional
Table
that specifies an element of the FROM clause within an UPDATE or DELETE to be the subject of the hint - applies only to certain backends.dialect_name – defaults to
*
, if specified as the name of a particular dialect, will apply these hints only when that dialect is in use.
-
attribute
- class sqlalchemy.sql.expression.ValuesBase¶
Supplies support for
ValuesBase.values()
to INSERT and UPDATE constructs.Class signature
class
sqlalchemy.sql.expression.ValuesBase
(sqlalchemy.sql.expression.UpdateBase
)-
attribute
sqlalchemy.sql.expression.ValuesBase.
select: Optional[Select[Any]] = None¶ SELECT statement for INSERT .. FROM SELECT
-
method
sqlalchemy.sql.expression.ValuesBase.
values(*args: Union[_DMLColumnKeyMapping[Any], Sequence[Any]], **kwargs: Any) Self ¶ Specify a fixed VALUES clause for an INSERT statement, or the SET clause for an UPDATE.
Note that the
Insert
andUpdate
constructs support per-execution time formatting of the VALUES and/or SET clauses, based on the arguments passed toConnection.execute()
. However, theValuesBase.values()
method can be used to “fix” a particular set of parameters into the statement.Multiple calls to
ValuesBase.values()
will produce a new construct, each one with the parameter list modified to include the new parameters sent. In the typical case of a single dictionary of parameters, the newly passed keys will replace the same keys in the previous construct. In the case of a list-based “multiple values” construct, each new list of values is extended onto the existing list of values.- Parameters:
**kwargs –
key value pairs representing the string key of a
Column
mapped to the value to be rendered into the VALUES or SET clause:users.insert().values(name="some name") users.update().where(users.c.id==5).values(name="some name")
*args –
As an alternative to passing key/value parameters, a dictionary, tuple, or list of dictionaries or tuples can be passed as a single positional argument in order to form the VALUES or SET clause of the statement. The forms that are accepted vary based on whether this is an
Insert
or anUpdate
construct.For either an
Insert
orUpdate
construct, a single dictionary can be passed, which works the same as that of the kwargs form:users.insert().values({"name": "some name"}) users.update().values({"name": "some new name"})
Also for either form but more typically for the
Insert
construct, a tuple that contains an entry for every column in the table is also accepted:users.insert().values((5, "some name"))
The
Insert
construct also supports being passed a list of dictionaries or full-table-tuples, which on the server will render the less common SQL syntax of “multiple values” - this syntax is supported on backends such as SQLite, PostgreSQL, MySQL, but not necessarily others:users.insert().values([ {"name": "some name"}, {"name": "some other name"}, {"name": "yet another name"}, ])
The above form would render a multiple VALUES statement similar to:
INSERT INTO users (name) VALUES (:name_1), (:name_2), (:name_3)
It is essential to note that passing multiple values is NOT the same as using traditional executemany() form. The above syntax is a special syntax not typically used. To emit an INSERT statement against multiple rows, the normal method is to pass a multiple values list to the
Connection.execute()
method, which is supported by all database backends and is generally more efficient for a very large number of parameters.See also
Sending Multiple Parameters - an introduction to the traditional Core method of multiple parameter set invocation for INSERTs and other statements.
The UPDATE construct also supports rendering the SET parameters in a specific order. For this feature refer to the
Update.ordered_values()
method.See also
-
attribute