SQLAlchemy 0.5 Documentation - module sqlalchemy.sql.expression

Module Functions

def alias(selectable, alias=None)

Return an Alias object.

An Alias represents any FromClause with an alternate name assigned within SQL, typically using the AS clause when generated, e.g. SELECT * FROM table AS aliasname.

Similar functionality is available via the alias() method available on all FromClause subclasses.

selectable

any FromClause subclass, such as a table, select statement, etc..

alias

string name to be assigned as the alias. If None, a random name will be generated.

def and_(*clauses)

Join a list of clauses together using the AND operator.

The & operator is also overloaded on all _CompareMixin subclasses to produce the same result.

def asc(column)

Return an ascending ORDER BY clause element.

e.g.:

order_by = [asc(table1.mycol)]

def between(ctest, cleft, cright)

Return a BETWEEN predicate clause.

Equivalent of SQL clausetest BETWEEN clauseleft AND clauseright.

The between() method on all _CompareMixin subclasses provides similar functionality.

def bindparam(key, value=None, shortname=None, type_=None, unique=False)

Create a bind parameter clause with the given key.

value: a default value for this bind parameter. a bindparam with a value is called a value-based bindparam.
type_: a sqlalchemy.types.TypeEngine object indicating the type of this bind param, will invoke type-specific bind parameter processing
shortname: deprecated.
unique: if True, bind params sharing the same name will have their underlying key modified to a uniquely generated name. mostly useful with value-based bind params.

def case(whens, value=None, else_=None)

Produce a CASE statement.

whens: A sequence of pairs, or alternatively a dict, to be translated into "WHEN / THEN" clauses.
value: Optional for simple case statements, produces a column expression as in "CASE <expr> WHEN ..."
else_: Optional as well, for case defaults produces the "ELSE" portion of the "CASE" statement.

The expressions used for THEN and ELSE, when specified as strings, will be interpreted as bound values. To specify textual SQL expressions for these, use the text(<string>) construct.

The expressions used for the WHEN criterion may only be literal strings when "value" is present, i.e. CASE table.somecol WHEN "x" THEN "y". Otherwise, literal strings are not accepted in this position, and either the text(<string>) or literal(<string>) constructs must be used to interpret raw string values.

Usage examples:

case([(orderline.c.qty > 100, item.c.specialprice),
      (orderline.c.qty > 10, item.c.bulkprice)
    ], else_=item.c.regularprice)
case(value=emp.c.type, whens={
        'engineer': emp.c.salary * 1.1,
        'manager':  emp.c.salary * 3,
    })

def cast(clause, totype, **kwargs)

Return a CAST function.

Equivalent of SQL CAST(clause AS totype).

Use with a TypeEngine subclass, i.e:

cast(table.c.unit_price * table.c.qty, Numeric(10,4))

or:

cast(table.c.timestamp, DATE)

def cloned_traverse(obj, opts, visitors)

def collate(expression, collation)

Return the clause expression COLLATE collation.

def column(text, type_=None)

Return a textual column clause, as would be in the columns clause of a SELECT statement.

The object returned is an instance of _ColumnClause, which represents the "syntactical" portion of the schema-level Column object.

text: the name of the column. Quoting rules will be applied to the clause like any other column name. For textual column constructs that are not to be quoted, use the literal_column() function.
type_: an optional TypeEngine object which will provide result-set translation for this column.

def delete(table, whereclause=None, **kwargs)

Return a Delete clause element.

Similar functionality is available via the delete() method on Table.

table: The table to be updated.
whereclause: A ClauseElement describing the WHERE condition of the UPDATE statement.

def desc(column)

Return a descending ORDER BY clause element.

e.g.:

order_by = [desc(table1.mycol)]

def distinct(expr)

Return a DISTINCT clause.

def except_(*selects, **kwargs)

Return an EXCEPT of multiple selectables.

The returned object is an instance of CompoundSelect.

*selects: a list of Select instances.
**kwargs: available keyword arguments are the same as those of select().

def except_all(*selects, **kwargs)

Return an EXCEPT ALL of multiple selectables.

The returned object is an instance of CompoundSelect.

*selects: a list of Select instances.
**kwargs: available keyword arguments are the same as those of select().

def exists(*args, **kwargs)

Return an EXISTS clause as applied to a Select object.

Calling styles are of the following forms:

# use on an existing select()
s = select([<columns>]).where(<criterion>)
s = exists(s)

# construct a select() at once
exists(['*'], **select_arguments).where(<criterion>)

# columns argument is optional, generates "EXISTS (SELECT *)"
# by default.
exists().where(<criterion>)

def extract(field, expr)

Return the clause extract(field FROM expr).

def insert(table, values=None, inline=False, **kwargs)

Return an Insert clause element.

Similar functionality is available via the insert() method on Table.

table: The table to be inserted into.
values: A dictionary which specifies the column specifications of the INSERT, and is optional. If left as None, the column specifications are determined from the bind parameters used during the compile phase of the INSERT statement. If the bind parameters also are None during the compile phase, then the column specifications will be generated from the full list of table columns.
prefixes: A list of modifier keywords to be inserted between INSERT and INTO, see Insert.prefix_with.
inline: if True, SQL defaults will be compiled 'inline' into the statement and not pre-executed.

If both values and compile-time bind parameters are present, the compile-time bind parameters override the information specified within values on a per-key basis.

The keys within values can be either Column 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 this INSERT statement's table, the statement will be correlated against the INSERT statement.

def intersect(*selects, **kwargs)

Return an INTERSECT of multiple selectables.

The returned object is an instance of CompoundSelect.

*selects: a list of Select instances.
**kwargs: available keyword arguments are the same as those of select().

def intersect_all(*selects, **kwargs)

Return an INTERSECT ALL of multiple selectables.

The returned object is an instance of CompoundSelect.

*selects: a list of Select instances.
**kwargs: available keyword arguments are the same as those of select().

def is_column(col)

True if col is an instance of ColumnElement.

def join(left, right, onclause=None, isouter=False)

Return a JOIN clause element (regular inner join).

The returned object is an instance of Join.

Similar functionality is also available via the join() method on any FromClause.

left: The left side of the join.
right: The right side of the join.
onclause: Optional criterion for the ON clause, is derived from foreign key relationships established between left and right otherwise.

To chain joins together, use the join() or outerjoin() methods on the resulting Join object.

def label(name, obj)

Return a _Label object for the given ColumnElement.

A label changes the name of an element in the columns clause of a SELECT statement, typically via the AS SQL keyword.

This functionality is more conveniently available via the label() method on ColumnElement.

name: label name
obj: a ColumnElement.

def literal(value, type_=None)

Return a literal clause, bound to a bind parameter.

Literal clauses are created automatically when non- ClauseElement objects (such as strings, ints, dates, etc.) are used in a comparison operation with a _CompareMixin subclass, such as a Column object. Use this function to force the generation of a literal clause, which will be created as a _BindParamClause with a bound value.

value: the value to be bound. Can be any Python object supported by the underlying DB-API, or is translatable via the given type argument.
type_: an optional TypeEngine which will provide bind-parameter translation for this literal.

def literal_column(text, type_=None)

Return a textual column expression, as would be in the columns clause of a SELECT statement.

The object returned supports further expressions in the same way as any other column object, including comparison, math and string operations. The type_ parameter is important to determine proper expression behavior (such as, '+' means string concatenation or numerical addition based on the type).

text: the text of the expression; can be any SQL expression. Quoting rules will not be applied. To specify a column-name expression which should be subject to quoting rules, use the column() function.
type_: an optional TypeEngine object which will provide result-set translation and additional expression semantics for this column. If left as None the type will be NullType.

def not_(clause)

Return a negation of the given clause, i.e. NOT(clause).

The ~ operator is also overloaded on all _CompareMixin subclasses to produce the same result.

def null()

Return a _Null object, which compiles to NULL in a sql statement.

def or_(*clauses)

Join a list of clauses together using the OR operator.

The | operator is also overloaded on all _CompareMixin subclasses to produce the same result.

def outerjoin(left, right, onclause=None)

Return an OUTER JOIN clause element.

The returned object is an instance of Join.

Similar functionality is also available via the outerjoin() method on any FromClause.

left: The left side of the join.
right: The right side of the join.
onclause: Optional criterion for the ON clause, is derived from foreign key relationships established between left and right otherwise.

To chain joins together, use the join() or outerjoin() methods on the resulting Join object.

def outparam(key, type_=None)

Create an 'OUT' parameter for usage in functions (stored procedures), for databases which support them.

The outparam can be used like a regular function parameter. The "output" value will be available from the ResultProxy object via its out_parameters attribute, which returns a dictionary containing the values.

def select(columns=None, whereclause=None, from_obj=[], **kwargs)

Returns a SELECT clause element.

Similar functionality is also available via the select() method on any FromClause.

The returned object is an instance of Select.

All arguments which accept ClauseElement arguments also accept string arguments, which will be converted as appropriate into either text() or literal_column() constructs.

columns

A list of ClauseElement objects, typically ColumnElement objects or subclasses, which will form the columns clause of the resulting statement. For all members which are instances of Selectable, the individual ColumnElement members of the Selectable will be added individually to the columns clause. For example, specifying a Table instance will result in all the contained Column objects within to be added to the columns clause.

This argument is not present on the form of select() available on Table.

whereclause

A ClauseElement expression which will be used to form the WHERE clause.

from_obj

A list of ClauseElement objects which will be added to the FROM clause of the resulting statement. Note that "from" objects are automatically located within the columns and whereclause ClauseElements. Use this parameter to explicitly specify "from" objects which are not automatically locatable. This could include Table objects that aren't otherwise present, or Join objects whose presence will supercede that of the Table objects already located in the other clauses.

**kwargs

Additional parameters include:

autocommit: indicates this SELECT statement modifies the database, and should be subject to autocommit behavior if no transaction has been started.
prefixes: a list of strings or ClauseElement objects to include directly after the SELECT keyword in the generated statement, for dialect-specific query features.
distinct=False: when True, applies a DISTINCT qualifier to the columns clause of the resulting statement.
use_labels=False: when True, the statement will be generated using labels for each column in the columns clause, which qualify each column with its parent table's (or aliases) name so that name conflicts between columns in different tables don't occur. The format of the label is <tablename>_<column>. The "c" collection of the resulting Select object will use these names as well for targeting column members.
for_update=False: when True, applies FOR UPDATE to the end of the resulting statement. Certain database dialects also support alternate values for this parameter, for example mysql supports "read" which translates to LOCK IN SHARE MODE, and oracle supports "nowait" which translates to FOR UPDATE NOWAIT.
correlate=True: indicates that this Select object should have its contained FromClause elements "correlated" to an enclosing Select object. This means that any ClauseElement instance within the "froms" collection of this Select which is also present in the "froms" collection of an enclosing select will not be rendered in the FROM clause of this select statement.
group_by: a list of ClauseElement objects which will comprise the GROUP BY clause of the resulting select.
having: a ClauseElement that will comprise the HAVING clause of the resulting select when GROUP BY is used.
order_by: a scalar or list of ClauseElement objects which will comprise the ORDER BY clause of the resulting select.
limit=None: a numerical value which usually compiles to a LIMIT expression in the resulting select. Databases that don't support LIMIT will attempt to provide similar functionality.
offset=None: a numeric value which usually compiles to an OFFSET expression in the resulting select. Databases that don't support OFFSET will attempt to provide similar functionality.
bind=None: an Engine or Connection instance to which the resulting Select ` object will be bound. The ``Select object will otherwise automatically bind to whatever Connectable instances can be located within its contained ClauseElement members.
scalar=False: deprecated. Use select(...).as_scalar() to create a "scalar column" proxy for an existing Select object.

def subquery(alias, *args, **kwargs)

Return an Alias object derived from a Select.

name: alias name

*args, **kwargs

all other arguments are delivered to the select() function.

def table(name, *columns)

Return a Table object.

This is a primitive version of the Table object, which is a subclass of this object.

def text(text, bind=None, *args, **kwargs)

Create literal text to be inserted into a query.

When constructing a query from a select(), update(), insert() or delete(), using plain strings for argument values will usually result in text objects being created automatically. Use this function when creating textual clauses outside of other ClauseElement objects, or optionally wherever plain text is to be used.

text: the text of the SQL statement to be created. use :<param> to specify bind parameters; they will be compiled to their engine-specific format.
bind: an optional connection or engine to be used for this text query.
autocommit=True: indicates this SELECT statement modifies the database, and should be subject to autocommit behavior if no transaction has been started.
bindparams: a list of bindparam() instances which can be used to define the types and/or initial values for the bind parameters within the textual statement; the keynames of the bindparams must match those within the text of the statement. The types will be used for pre-processing on bind values.
typemap: a dictionary mapping the names of columns represented in the SELECT clause of the textual statement to type objects, which will be used to perform post-processing on columns within the result set (for textual statements that produce result sets).

def union(*selects, **kwargs)

Return a UNION of multiple selectables.

The returned object is an instance of CompoundSelect.

A similar union() method is available on all FromClause subclasses.

*selects: a list of Select instances.
**kwargs: available keyword arguments are the same as those of select().

def union_all(*selects, **kwargs)

Return a UNION ALL of multiple selectables.

The returned object is an instance of CompoundSelect.

A similar union_all() method is available on all FromClause subclasses.

*selects: a list of Select instances.
**kwargs: available keyword arguments are the same as those of select().

def update(table, whereclause=None, values=None, inline=False, **kwargs)

Return an Update clause element.

Similar functionality is available via the update() method on Table.

table: The table to be updated.
whereclause: A ClauseElement describing the WHERE condition of the UPDATE statement.
values: A dictionary which specifies the SET conditions of the UPDATE, and is optional. If left as None, the SET conditions are determined from the bind parameters used during the compile phase of the UPDATE statement. If the bind parameters also are None during the compile phase, then the SET conditions will be generated from the full list of table columns.
inline: if True, SQL defaults will be compiled 'inline' into the statement and not pre-executed.

If both values and compile-time bind parameters are present, the compile-time bind parameters override the information specified within values on a per-key basis.

The keys within values can be either Column 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 this UPDATE statement's table, the statement will be correlated against the UPDATE statement.

class Alias(FromClause)

Represents an table or selectable alias (AS).

Represents an alias, as typically applied to any table or sub-select within a SQL statement using the AS keyword (or without the keyword on certain databases such as Oracle).

This object is constructed from the alias() module level function as well as the alias() method available on all FromClause subclasses.

def __init__(self, selectable, alias=None)

Construct a new Alias.

description = property()

bind = property()

def get_children(self, column_collections=True, aliased_selectables=True, **kwargs)

def is_derived_from(self, fromclause)

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class _BinaryExpression(ColumnElement)

Represent an expression that is LEFT <operator> RIGHT.

def __init__(self, left, right, operator, type_=None, negate=None, modifiers=None)

Construct a new _BinaryExpression.

def compare(self, other)

Compare this _BinaryExpression against the given _BinaryExpression.

def get_children(self, **kwargs)

def self_group(self, against=None)

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class _BindParamClause(ColumnElement)

Represent a bind parameter.

Public constructor is the bindparam() function.

def __init__(self, key, value, type_=None, unique=False, isoutparam=False, shortname=None)

Construct a _BindParamClause.

key: the key for this bind param. Will be used in the generated SQL statement for dialects that use named parameters. This value may be modified when part of a compilation operation, if other _BindParamClause objects exist with the same key, or if its length is too long and truncation is required.
value: Initial value for this bind param. This value may be overridden by the dictionary of parameters sent to statement compilation/execution.
shortname: deprecated.
type_: A TypeEngine object that will be used to pre-process the value corresponding to this _BindParamClause at execution time.
unique: if True, the key name of this BindParamClause will be modified if another _BindParamClause of the same name already has been located within the containing ClauseElement.
isoutparam: if True, the parameter should be treated like a stored procedure "OUT" parameter.

def bind_processor(self, dialect)

def compare(self, other)

Compare this _BindParamClause to the given clause.

Since compare() is meant to compare statement syntax, this method returns True if the two _BindParamClauses have just the same type.

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class BooleanClauseList(ClauseList,ColumnElement)

def __init__(self, *clauses, **kwargs)

Construct a new BooleanClauseList.

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class _CalculatedClause(ColumnElement)

Describe a calculated SQL expression that has a type, like CASE.

Extends ColumnElement to provide column-level comparison operators.

def __init__(self, name, *clauses, **kwargs)

Construct a new _CalculatedClause.

def execute(self)

def get_children(self, **kwargs)

key = property()

clauses = property()

def scalar(self)

def select(self)

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class _Cast(ColumnElement)

def __init__(self, clause, totype, **kwargs)

Construct a new _Cast.

def get_children(self, **kwargs)

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class ClauseElement(Visitable)

Base class for elements of a programmatically constructed SQL expression.

bind = property()

def compare(self, other)

Compare this ClauseElement to the given ClauseElement.

Subclasses should override the default behavior, which is a straight identity comparison.

def compile(self, bind=None, column_keys=None, compiler=None, dialect=None, inline=False)

Compile this SQL expression.

Uses the given Compiler, or the given AbstractDialect or Engine to create a Compiler. If no compiler arguments are given, tries to use the underlying Engine this ClauseElement is bound to to create a Compiler, if any.

Finally, if there is no bound Engine, uses an DefaultDialect to create a default Compiler.

parameters is a dictionary representing the default bind parameters to be used with the statement. If parameters is a list, it is assumed to be a list of dictionaries and the first dictionary in the list is used with which to compile against.

The bind parameters can in some cases determine the output of the compilation, such as for UPDATE and INSERT statements the bind parameters that are present determine the SET and VALUES clause of those statements.

def execute(self, *multiparams, **params)

Compile and execute this ClauseElement.

def get_children(self, **kwargs)

Return immediate child elements of this ClauseElement.

This is used for visit traversal.

**kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

def params(self, *optionaldict, **kwargs)

Return a copy with bindparam() elments replaced.

Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:

>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}

def scalar(self, *multiparams, **params)

Compile and execute this ClauseElement, returning the result's scalar representation.

def self_group(self, against=None)

def unique_params(self, *optionaldict, **kwargs)

Return a copy with bindparam() elments replaced.

Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.

def __and__(self, other)

def __invert__(self)

def __or__(self, other)

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class ClauseList(ClauseElement)

Describe a list of clauses, separated by an operator.

By default, is comma-separated, such as a column listing.

def __init__(self, *clauses, **kwargs)

Construct a new ClauseList.

def append(self, clause)

def compare(self, other)

Compare this ClauseList to the given ClauseList, including a comparison of all the clause items.

def get_children(self, **kwargs)

def self_group(self, against=None)

def __iter__(self)

def __len__(self)

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class _ColumnClause(_Immutable,ColumnElement)

Represents a generic column expression from any textual string.

This includes columns associated with tables, aliases and select statements, but also any arbitrary text. May or may not be bound to an underlying Selectable. _ColumnClause is usually created publically via the column() function or the literal_column() function.

text: the text of the element.
selectable: parent selectable.
type: TypeEngine object which can associate this _ColumnClause with a type.
is_literal: if True, the _ColumnClause is assumed to be an exact expression that will be delivered to the output with no quoting rules applied regardless of case sensitive settings. the literal_column() function is usually used to create such a _ColumnClause.

def __init__(self, text, selectable=None, type_=None, is_literal=False)

Construct a new _ColumnClause.

def label(self, name)

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class ColumnCollection(OrderedProperties)

An ordered dictionary that stores a list of ColumnElement instances.

Overrides the __eq__() method to produce SQL clauses between sets of correlated columns.

def __init__(self, *cols)

Construct a new ColumnCollection.

def add(self, column)

Add a column to this collection.

The key attribute of the column will be used as the hash key for this dictionary.

def contains_column(self, col)

def extend(self, iter)

def remove(self, column)

def replace(self, column)

add the given column to this collection, removing unaliased versions of this column as well as existing columns with the same key.

e.g.:
t = Table('sometable', Column('col1', Integer))
t.replace_unalised(Column('col1', Integer, key='columnone'))
will remove the original 'col1' from the collection, and add the new column under the name 'columnname'.

Used by schema.Column to override columns during table reflection.

def __contains__(self, other)

def __eq__(self, other)

def __setitem__(self, key, value)

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class ColumnElement(ClauseElement,_CompareMixin)

Represent an element that is usable within the "column clause" portion of a SELECT statement.

This includes columns associated with tables, aliases, and subqueries, expressions, function calls, SQL keywords such as NULL, literals, etc. ColumnElement is the ultimate base class for all such elements.

ColumnElement supports the ability to be a proxy element, which indicates that the ColumnElement may be associated with a Selectable which was derived from another Selectable. An example of a "derived" Selectable is an Alias of a Table.

A ColumnElement, by subclassing the _CompareMixin mixin class, provides the ability to generate new ClauseElement objects using Python expressions. See the _CompareMixin docstring for more details.

def shares_lineage(self, othercolumn)

Return True if the given ColumnElement has a common ancestor to this ColumnElement.

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class ColumnOperators(Operators)

Defines comparison and math operations.

def asc(self)

def between(self, cleft, cright)

def collate(self, collation)

def concat(self, other)

def contains(self, other, **kwargs)

def desc(self)

def distinct(self)

def endswith(self, other, **kwargs)

def ilike(self, other, escape=None)

def in_(self, other)

def like(self, other, escape=None)

def match(self, other, **kwargs)

def startswith(self, other, **kwargs)

def __add__(self, other)

def __div__(self, other)

def __eq__(self, other)

def __ge__(self, other)

def __gt__(self, other)

def __le__(self, other)

def __lt__(self, other)

def __mod__(self, other)

def __mul__(self, other)

def __ne__(self, other)

def __radd__(self, other)

def __rdiv__(self, other)

def __rmul__(self, other)

def __rsub__(self, other)

def __sub__(self, other)

def __truediv__(self, other)

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class ColumnSet(OrderedSet)

def contains_column(self, col)

def extend(self, cols)

def __add__(self, other)

def __eq__(self, other)

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class _CompareMixin(ColumnOperators)

Defines comparison and math operations for ClauseElement instances.

def asc(self)

Produce a ASC clause, i.e. <columnname> ASC

def between(self, cleft, cright)

Produce a BETWEEN clause, i.e. <column> BETWEEN <cleft> AND <cright>

def collate(self, collation)

Produce a COLLATE clause, i.e. <column> COLLATE utf8_bin

def contains(self, other, escape=None)

Produce the clause LIKE '%<other>%'

def desc(self)

Produce a DESC clause, i.e. <columnname> DESC

def distinct(self)

Produce a DISTINCT clause, i.e. DISTINCT <columnname>

def endswith(self, other, escape=None)

Produce the clause LIKE '%<other>'

def in_(self, other)

def label(self, name)

Produce a column label, i.e. <columnname> AS <name>.

if 'name' is None, an anonymous label name will be generated.

def match(self, other)

Produce a MATCH clause, i.e. MATCH '<other>'

The allowed contents of other are database backend specific.

def op(self, operator)

produce a generic operator function.

e.g.:

somecolumn.op("*")(5)

produces:

somecolumn * 5

operator: a string which will be output as the infix operator between this ClauseElement and the expression passed to the generated function.

def operate(self, op, *other, **kwargs)

def reverse_operate(self, op, other, **kwargs)

def startswith(self, other, escape=None)

Produce the clause LIKE '<other>%'

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class CompoundSelect(_SelectBaseMixin,FromClause)

def __init__(self, keyword, *selects, **kwargs)

Construct a new CompoundSelect.

bind = property()

def get_children(self, column_collections=True, **kwargs)

def self_group(self, against=None)

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class Delete(_UpdateBase)

def __init__(self, table, whereclause, bind=None, **kwargs)

Construct a new Delete.

def get_children(self, **kwargs)

def where(self, whereclause)

Add the given WHERE clause to a newly returned delete construct.

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class _Exists(_UnaryExpression)

def __init__(self, *args, **kwargs)

Construct a new _Exists.

def correlate(self, fromclause)

def select(self, whereclause=None, **params)

def select_from(self, clause)

return a new exists() construct with the given expression set as its FROM clause.

def where(self, clause)

return a new exists() construct with the given expression added to its WHERE clause, joined to the existing clause via AND, if any.

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class FromClause(Selectable)

Represent an element that can be used within the FROM clause of a SELECT statement.

def alias(self, name=None)

return an alias of this FromClause against another FromClause.

c = property()

columns = property()

def correspond_on_equivalents(self, column, equivalents)

def corresponding_column(self, column, require_embedded=False)

Given a ColumnElement, return the exported ColumnElement object from this Selectable which corresponds to that original Column via a common anscestor column.

column: the target ColumnElement to be matched
require_embedded: only return corresponding columns for the given ColumnElement, if the given ColumnElement is actually present within a sub-element of this FromClause. Normally the column will match if it merely shares a common anscestor with one of the exported columns of this FromClause.

def count(self, whereclause=None, **params)

return a SELECT COUNT generated against this FromClause.

description = property()

def is_derived_from(self, fromclause)

Return True if this FromClause is 'derived' from the given FromClause.

An example would be an Alias of a Table is derived from that Table.

def join(self, right, onclause=None, isouter=False)

return a join of this FromClause against another FromClause.

def outerjoin(self, right, onclause=None)

return an outer join of this FromClause against another FromClause.

primary_key = property()

foreign_keys = property()

def replace_selectable(self, old, alias)

replace all occurences of FromClause 'old' with the given Alias object, returning a copy of this FromClause.

def select(self, whereclause=None, **params)

return a SELECT of this FromClause.

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class _FromGrouping(FromClause)

Represent a grouping of a FROM clause

def __init__(self, element)

Construct a new _FromGrouping.

c = property()

columns = property()

def get_children(self, **kwargs)

def __getattr__(self, attr)

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class _Function(_CalculatedClause,FromClause)

Describe a SQL function.

Extends _CalculatedClause, turn the clauselist into function arguments, also adds a packagenames argument.

def __init__(self, name, *clauses, **kwargs)

Construct a new _Function.

def get_children(self, **kwargs)

key = property()

columns = property()

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class _FunctionGenerator(object)

Generate _Function objects based on getattr calls.

def __init__(self, **opts)

Construct a new _FunctionGenerator.

def __call__(self, *c, **kwargs)

def __getattr__(self, name)

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class _Grouping(ColumnElement)

Represent a grouping within a column expression

def __init__(self, element)

Construct a new _Grouping.

def get_children(self, **kwargs)

key = property()

def __getattr__(self, attr)

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class _IdentifiedClause(ClauseElement)

def __init__(self, ident)

Construct a new _IdentifiedClause.

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class _Immutable(object)

mark a ClauseElement as 'immutable' when expressions are cloned.

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class Insert(_ValuesBase)

def __init__(self, table, values=None, inline=False, bind=None, prefixes=None, **kwargs)

Construct a new Insert.

def get_children(self, **kwargs)

def prefix_with(self, clause)

Add a word or expression between INSERT and INTO. Generative.

If multiple prefixes are supplied, they will be separated with spaces.

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class Join(FromClause)

represent a JOIN construct between two FromClause elements.

The public constructor function for Join is the module-level join() function, as well as the join() method available off all FromClause subclasses.

def __init__(self, left, right, onclause=None, isouter=False)

Construct a new Join.

def alias(self, name=None)

Create a Select out of this Join clause and return an Alias of it.

The Select is not correlating.

description = property()

bind = property()

def get_children(self, **kwargs)

def is_derived_from(self, fromclause)

def select(self, whereclause=None, fold_equivalents=False, **kwargs)

Create a Select from this Join.

whereclause: the WHERE criterion that will be sent to the select() function
fold_equivalents: based on the join criterion of this Join, do not include repeat column names in the column list of the resulting select, for columns that are calculated to be "equivalent" based on the join criterion of this Join. This will recursively apply to any joins directly nested by this one as well.
**kwargs: all other kwargs are sent to the underlying select() function. See the select() module level function for details.

def self_group(self, against=None)

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class _Label(ColumnElement)

Represents a column label (AS).

Represent a label, as typically applied to any column-level element using the AS sql keyword.

This object is constructed from the label() module level function as well as the label() method available on all ColumnElement subclasses.

def __init__(self, name, element, type_=None)

Construct a new _Label.

def get_children(self, **kwargs)

proxy_set = property()

primary_key = property()

foreign_keys = property()

proxies = property()

base_columns = property()

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class _Null(ColumnElement)

Represent the NULL keyword in a SQL statement.

Public constructor is the null() function.

def __init__(self)

Construct a new _Null.

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class Operators(object)

def op(self, opstring)

def operate(self, op, *other, **kwargs)

def reverse_operate(self, op, other, **kwargs)

def __and__(self, other)

def __invert__(self)

def __or__(self, other)

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class ReleaseSavepointClause(_IdentifiedClause)

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class RollbackToSavepointClause(_IdentifiedClause)

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class SavepointClause(_IdentifiedClause)

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class _ScalarSelect(_Grouping)

def __init__(self, element)

Construct a new _ScalarSelect.

c = property()

columns = property()

def self_group(self, **kwargs)

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class Select(_SelectBaseMixin,FromClause)

Represents a SELECT statement.

Select statements support appendable clauses, as well as the ability to execute themselves and return a result set.

def __init__(self, columns, whereclause=None, from_obj=None, distinct=False, having=None, correlate=True, prefixes=None, **kwargs)

Construct a Select object.

The public constructor for Select is the select() function; see that function for argument descriptions.

Additional generative and mutator methods are available on the _SelectBaseMixin superclass.

def append_column(self, column)

append the given column expression to the columns clause of this select() construct.

def append_correlation(self, fromclause)

append the given correlation expression to this select() construct.

def append_from(self, fromclause)

append the given FromClause expression to this select() construct's FROM clause.

def append_having(self, having)

append the given expression to this select() construct's HAVING criterion.

The expression will be joined to existing HAVING criterion via AND.