Class SQLCompiler

Declaration

Methods

• ▷ def __init__(self, query, connection, using)

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• ▷ def apply_converters(self, rows, converters)

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• ▶ def as_sql(self, with_limits=True, with_col_aliases=False)

  Create the SQL for this query. Return the SQL string and list of parameters.

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  If 'with_limits' is False, any limit/offset information is not included
  in the query.

  Overrides

  This method is overriden in:

  • django.db.models.sql.compiler.SQLInsertCompiler
  • django.db.models.sql.compiler.SQLDeleteCompiler
  • django.db.models.sql.compiler.SQLUpdateCompiler
  • django.db.models.sql.compiler.SQLAggregateCompiler
• ▶ def as_subquery_condition(self, alias, columns, compiler)

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  Overrides

  This method is overriden in:

  • django.db.backends.mysql.compiler.SQLCompiler
• ▷ def collapse_group_by(self, expressions, having)

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• ▷ def compile(self, node)

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• ▷ def deferred_to_columns(self)

  Convert the self.deferred_loading data structure to mapping of table names to sets of column names which are to be loaded. Return the dictionary.

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• ▶ def execute_sql(self, result_type=MULTI, chunked_fetch=False, chunk_size=GET_ITERATOR_CHUNK_SIZE)

  Run the query against the database and return the result(s). The return value is a single data item if result_type is SINGLE, or an iterator over the results if the result_type is MULTI.

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  result_type is either MULTI (use fetchmany() to retrieve all rows),
  SINGLE (only retrieve a single row), or None. In this last case, the
  cursor is returned if any query is executed, since it's used by
  subclasses such as InsertQuery). It's possible, however, that no query
  is needed, as the filters describe an empty set. In that case, None is
  returned, to avoid any unnecessary database interaction.

  Overrides

  This method is overriden in:

  • django.db.models.sql.compiler.SQLInsertCompiler
  • django.db.models.sql.compiler.SQLUpdateCompiler
• ▷ def explain_query(self)

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• ▷ def find_ordering_name(self, name, opts, alias=None, default_order='ASC', already_seen=None)

  Return the table alias (the name might be ambiguous, the alias will not be) and column name for ordering by the given 'name' parameter. The 'name' is of the form 'field1__field2__...__fieldN'.

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• ▷ def get_combinator_sql(self, combinator, all)

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• ▷ def get_converters(self, expressions)

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• ▶ def get_default_columns(self, start_alias=None, opts=None, from_parent=None)

  Compute the default columns for selecting every field in the base

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  model. Will sometimes be called to pull in related models (e.g. via
  select_related), in which case "opts" and "start_alias" will be given
  to provide a starting point for the traversal.
  
  Return a list of strings, quoted appropriately for use in SQL
  directly, as well as a set of aliases used in the select statement (if
  'as_pairs' is True, return a list of (alias, col_name) pairs instead
  of strings as the first component and None as the second component).

• ▶ def get_distinct(self)

  Return a quoted list of fields to use in DISTINCT ON part of the query.

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  This method can alter the tables in the query, and thus it must be
  called before get_from_clause().

• ▷ def get_extra_select(self, order_by, select)

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• ▶ def get_from_clause(self)

  Return a list of strings that are joined together to go after the

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  "FROM" part of the query, as well as a list any extra parameters that
  need to be included. Subclasses, can override this to create a
  from-clause via a "select".
  
  This should only be called after any SQL construction methods that
  might change the tables that are needed. This means the select columns,
  ordering, and distinct must be done first.

• ▶ def get_group_by(self, select, order_by)

  Return a list of 2-tuples of form (sql, params).

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  The logic of what exactly the GROUP BY clause contains is hard
  to describe in other words than "if it passes the test suite,
  then it is correct".

• ▶ def get_order_by(self)

  Return a list of 2-tuples of form (expr, (sql, params, is_ref)) for the ORDER BY clause.

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  The order_by clause can alter the select clause (for example it
  can add aliases to clauses that do not yet have one, or it can
  add totally new select clauses).

• ▶ def get_related_selections(self, select, opts=None, root_alias=None, cur_depth=1, requested=None, ...)

  Fill in the information needed for a select_related query. The current

  def get_related_selections(

  self,

  select,

  opts=None,

  root_alias=None,

  cur_depth=1,

  requested=None,

  restricted=None,

  )

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  depth is measured as the number of connections away from the root model
  (for example, cur_depth=1 means we are looking at models with direct
  connections to the root model).

• ▶ def get_select(self)

  Return three values:

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  - a list of 3-tuples of (expression, (sql, params), alias)
  - a klass_info structure,
  - a dictionary of annotations
  
  The (sql, params) is what the expression will produce, and alias is the
  "AS alias" for the column (possibly None).
  
  The klass_info structure contains the following information:
  - The base model of the query.
  - Which columns for that model are present in the query (by
    position of the select clause).
  - related_klass_infos: [f, klass_info] to descent into
  
  The annotations is a dictionary of {'attname': column position} values.

• ▷ def get_select_for_update_of_arguments(self)

  Return a quoted list of arguments for the SELECT FOR UPDATE OF part of the query.

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• ▷ def has_results(self)

  Backends (e.g. NoSQL) can override this in order to use optimized versions of "query has any results."

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• ▶ def pre_sql_setup(self)

  Do any necessary class setup immediately prior to producing SQL. This is for things that can't necessarily be done in __init__ because we might not have all the pieces in place at that time.

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  Overrides

  This method is overriden in:

  • django.db.models.sql.compiler.SQLUpdateCompiler
• ▷ def quote_name_unless_alias(self, name)

  A wrapper around connection.ops.quote_name that doesn't quote aliases for table names. This avoids problems with some SQL dialects that treat quoted strings specially (e.g. PostgreSQL).

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• ▶ def results_iter(self, results=None, tuple_expected=False, chunked_fetch=False, ...)

  Return an iterator over the results from executing this query.

  def results_iter(

  self,

  results=None,

  tuple_expected=False,

  chunked_fetch=False,

  chunk_size=GET_ITERATOR_CHUNK_SIZE,

  )

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• ▷ def setup_query(self)

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Subclasses

• django.db.backends.mysql.compiler.SQLCompiler
• django.db.models.sql.compiler.SQLInsertCompiler
• django.db.models.sql.compiler.SQLDeleteCompiler
• django.db.models.sql.compiler.SQLUpdateCompiler
• django.db.models.sql.compiler.SQLAggregateCompiler

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