def get_dml_range(ir_stmt: irast.MutatingStmt, dml_stmt: pgast.DML, *,
ctx: context.CompilerContextLevel) -> pgast.CommonTableExpr:
"""Create a range CTE for the given DML statement.
:param ir_stmt:
IR of the statement.
:param dml_stmt:
SQL DML node instance.
:return:
A CommonTableExpr node representing the range affected
by the DML statement.
"""
target_ir_set = ir_stmt.subject
ir_qual_expr = ir_stmt.where
with ctx.newscope() as scopectx, scopectx.newrel() as subctx:
subctx.expr_exposed = False
range_stmt = subctx.rel
# init_stmt() has associated all top-level paths with
# the main query, which is at the very bottom.
# Hoist that scope to the modification range statement
# instead.
for path_id, stmt in ctx.path_scope.items():
if stmt is ctx.rel or path_id == ir_stmt.subject.path_id:
scopectx.path_scope[path_id] = range_stmt
if ir_stmt.parent_stmt is not None:
iterator_set = ir_stmt.parent_stmt.iterator_stmt
else:
iterator_set = None
if iterator_set is not None:
scopectx.path_scope[iterator_set.path_id] = range_stmt
relctx.update_scope(iterator_set, range_stmt, ctx=subctx)
iterator_rvar = clauses.compile_iterator_expr(range_stmt,
iterator_set,
ctx=subctx)
relctx.include_rvar(range_stmt,
iterator_rvar,
iterator_set.path_id,
ctx=subctx)
dispatch.compile(target_ir_set, ctx=subctx)
pathctx.get_path_identity_output(range_stmt,
target_ir_set.path_id,
env=subctx.env)
if ir_qual_expr is not None:
range_stmt.where_clause = astutils.extend_binop(
range_stmt.where_clause,
clauses.compile_filter_clause(ir_qual_expr, ctx=subctx))
range_cte = pgast.CommonTableExpr(query=range_stmt,
name=ctx.env.aliases.get('range'))
return range_cte
def process_link_values(ir_stmt,
ir_expr,
target_tab,
tab_cols,
col_data,
dml_rvar,
sources,
props_only,
target_is_scalar,
iterator_cte,
*,
ctx=context.CompilerContext) -> pgast.CommonTableExpr:
"""Unpack data from an update expression into a series of selects.
:param ir_expr:
IR of the INSERT/UPDATE body element.
:param target_tab:
The link table being updated.
:param tab_cols:
A sequence of columns in the table being updated.
:param col_data:
Expressions used to populate well-known columns of the link
table such as std::source and std::__type__.
:param sources:
A list of relations which must be joined into the data query
to resolve expressions in *col_data*.
:param props_only:
Whether this link update only touches link properties.
:param target_is_scalar:
Whether the link target is an ScalarType.
:param iterator_cte:
CTE representing the iterator range in the FOR clause of the
EdgeQL DML statement.
"""
with ctx.newscope() as newscope, newscope.newrel() as subrelctx:
row_query = subrelctx.rel
relctx.include_rvar(row_query, dml_rvar, ctx=subrelctx)
subrelctx.path_scope[ir_stmt.subject.path_id] = row_query
if iterator_cte is not None:
iterator_rvar = dbobj.rvar_for_rel(iterator_cte,
lateral=True,
env=subrelctx.env)
relctx.include_rvar(row_query,
iterator_rvar,
iterator_cte.query.path_id,
aspect='value',
ctx=subrelctx)
with subrelctx.newscope() as sctx, sctx.subrel() as input_rel_ctx:
input_rel = input_rel_ctx.rel
if iterator_cte is not None:
input_rel_ctx.path_scope[iterator_cte.query.path_id] = \
row_query
input_rel_ctx.expr_exposed = False
input_rel_ctx.shape_format = context.ShapeFormat.FLAT
input_rel_ctx.volatility_ref = pathctx.get_path_identity_var(
row_query, ir_stmt.subject.path_id, env=input_rel_ctx.env)
dispatch.compile(ir_expr, ctx=input_rel_ctx)
input_stmt = input_rel
input_rvar = pgast.RangeSubselect(
subquery=input_rel,
lateral=True,
alias=pgast.Alias(aliasname=ctx.env.aliases.get('val')))
row = pgast.ImplicitRowExpr()
source_data = {}
if input_stmt.op is not None:
# UNION
input_stmt = input_stmt.rarg
path_id = ir_expr.path_id
output = pathctx.get_path_value_output(input_stmt, path_id, env=ctx.env)
if isinstance(output, pgast.TupleVar):
for element in output.elements:
name = element.path_id.rptr_name()
if name is None:
name = element.path_id[-1].name
colname = common.edgedb_name_to_pg_name(name)
source_data.setdefault(colname,
dbobj.get_column(input_rvar, element.name))
else:
if target_is_scalar:
target_ref = pathctx.get_rvar_path_value_var(input_rvar,
path_id,
env=ctx.env)
else:
target_ref = pathctx.get_rvar_path_identity_var(input_rvar,
path_id,
env=ctx.env)
source_data['std::target'] = target_ref
if not target_is_scalar and 'std::target' not in source_data:
target_ref = pathctx.get_rvar_path_identity_var(input_rvar,
path_id,
env=ctx.env)
source_data['std::target'] = target_ref
for col in tab_cols:
expr = col_data.get(col)
if expr is None:
expr = source_data.get(col)
if expr is None:
if tab_cols[col]['column_default'] is not None:
expr = pgast.LiteralExpr(expr=tab_cols[col]['column_default'])
else:
expr = pgast.Constant(val=None)
row.args.append(expr)
row_query.target_list = [
pgast.ResTarget(val=pgast.Indirection(arg=pgast.TypeCast(
arg=row, type_name=pgast.TypeName(name=target_tab)),
indirection=[pgast.Star()]))
]
row_query.from_clause += list(sources) + [input_rvar]
link_rows = pgast.CommonTableExpr(query=row_query,
name=ctx.env.aliases.get(hint='r'))
return link_rows
def process_linkprop_update(ir_stmt: irast.MutatingStmt, ir_expr: irast.Base,
wrapper: pgast.Query,
dml_cte: pgast.CommonTableExpr, *,
ctx: context.CompilerContextLevel) -> None:
"""Perform link property updates to a link relation.
:param ir_stmt:
IR of the statement.
:param ir_expr:
IR of the UPDATE body element.
:param wrapper:
Top-level SQL query.
:param dml_cte:
CTE representing the SQL UPDATE to the main relation of the Object.
"""
toplevel = ctx.toplevel_stmt
rptr = ir_expr.rptr
ptrcls = rptr.ptrcls
target_is_scalar = isinstance(rptr.target, s_scalars.ScalarType)
target_tab = dbobj.range_for_ptrcls(ptrcls,
'>',
include_overlays=False,
env=ctx.env)
if target_is_scalar:
target_tab_name = (target_tab.schema, target_tab.name)
else:
target_tab_name = common.link_name_to_table_name(ptrcls.shortname,
catenate=False)
tab_cols = \
ctx.env.backend._type_mech.get_cached_table_columns(target_tab_name)
assert tab_cols, "could not get cols for {!r}".format(target_tab_name)
dml_cte_rvar = pgast.RangeVar(
relation=dml_cte,
alias=pgast.Alias(aliasname=ctx.env.aliases.get('m')))
cond = astutils.new_binop(
pathctx.get_rvar_path_identity_var(dml_cte_rvar,
ir_stmt.subject.path_id,
env=ctx.env),
dbobj.get_column(target_tab, 'std::source'), ast.ops.EQ)
targets = []
for prop_el in ir_expr.shape:
ptrname = prop_el.rptr.ptrcls.shortname
with ctx.new() as input_rel_ctx:
input_rel_ctx.expr_exposed = False
input_rel = dispatch.compile(prop_el.expr, ctx=input_rel_ctx)
targets.append(
pgast.UpdateTarget(name=common.edgedb_name_to_pg_name(ptrname),
val=input_rel))
updstmt = pgast.UpdateStmt(relation=target_tab,
where_clause=cond,
targets=targets,
from_clause=[dml_cte_rvar])
updcte = pgast.CommonTableExpr(query=updstmt,
name=ctx.env.aliases.get(
ptrcls.shortname.name))
toplevel.ctes.append(updcte)
def process_link_update(
ir_stmt: irast.MutatingStmt, ir_expr: irast.Base, props_only: bool,
wrapper: pgast.Query, dml_cte: pgast.CommonTableExpr,
iterator_cte: pgast.CommonTableExpr, *,
ctx: context.CompilerContextLevel) -> typing.Optional[pgast.Query]:
"""Perform updates to a link relation as part of a DML statement.
:param ir_stmt:
IR of the statement.
:param ir_expr:
IR of the INSERT/UPDATE body element.
:param props_only:
Whether this link update only touches link properties.
:param wrapper:
Top-level SQL query.
:param dml_cte:
CTE representing the SQL INSERT or UPDATE to the main
relation of the Object.
:param iterator_cte:
CTE representing the iterator range in the FOR clause of the
EdgeQL DML statement.
"""
toplevel = ctx.toplevel_stmt
edgedb_ptr_tab = pgast.RangeVar(
relation=pgast.Relation(schemaname='edgedb', name='pointer'),
alias=pgast.Alias(aliasname=ctx.env.aliases.get(hint='ptr')))
ltab_alias = edgedb_ptr_tab.alias.aliasname
rptr = ir_expr.rptr
ptrcls = rptr.ptrcls
target_is_scalar = isinstance(ptrcls.target, s_scalars.ScalarType)
path_id = rptr.source.path_id.extend(ptrcls, rptr.direction,
rptr.target.scls)
# The links in the dml class shape have been derived,
# but we must use the correct specialized link class for the
# base material type.
mptrcls = ptrcls.material_type()
# Lookup link class id by link name.
lname_to_id = pgast.CommonTableExpr(query=pgast.SelectStmt(
from_clause=[edgedb_ptr_tab],
target_list=[
pgast.ResTarget(val=pgast.ColumnRef(name=[ltab_alias, 'id']))
],
where_clause=astutils.new_binop(
lexpr=pgast.ColumnRef(name=[ltab_alias, 'name']),
rexpr=pgast.Constant(val=mptrcls.name),
op=ast.ops.EQ)),
name=ctx.env.aliases.get(hint='lid'))
lname_to_id_rvar = pgast.RangeVar(relation=lname_to_id)
toplevel.ctes.append(lname_to_id)
target_rvar = dbobj.range_for_ptrcls(mptrcls,
'>',
include_overlays=False,
env=ctx.env)
target_alias = target_rvar.alias.aliasname
if target_is_scalar:
target_tab_name = (target_rvar.relation.schemaname,
target_rvar.relation.name)
else:
target_tab_name = common.link_name_to_table_name(mptrcls.shortname,
catenate=False)
tab_cols = \
ctx.env.backend._type_mech.get_cached_table_columns(target_tab_name)
assert tab_cols, "could not get cols for {!r}".format(target_tab_name)
dml_cte_rvar = pgast.RangeVar(
relation=dml_cte,
alias=pgast.Alias(aliasname=ctx.env.aliases.get('m')))
col_data = {
'ptr_item_id':
pgast.ColumnRef(name=[lname_to_id.name, 'id']),
'std::source':
pathctx.get_rvar_path_identity_var(dml_cte_rvar,
ir_stmt.subject.path_id,
env=ctx.env)
}
# Drop all previous link records for this source.
delcte = pgast.CommonTableExpr(query=pgast.DeleteStmt(
relation=target_rvar,
where_clause=astutils.new_binop(
lexpr=col_data['std::source'],
op=ast.ops.EQ,
rexpr=pgast.ColumnRef(name=[target_alias, 'std::source'])),
using_clause=[dml_cte_rvar],
returning_list=[
pgast.ResTarget(val=pgast.ColumnRef(
name=[target_alias, pgast.Star()]))
]),
name=ctx.env.aliases.get(hint='d'))
pathctx.put_path_value_rvar(delcte.query,
path_id.ptr_path(),
target_rvar,
env=ctx.env)
# Record the effect of this removal in the relation overlay
# context to ensure that the RETURNING clause potentially
# referencing this link yields the expected results.
overlays = ctx.env.rel_overlays[ptrcls.shortname]
overlays.append(('except', delcte))
toplevel.ctes.append(delcte)
# Turn the IR of the expression on the right side of :=
# into a subquery returning records for the link table.
data_cte = process_link_values(ir_stmt,
ir_expr,
target_tab_name,
tab_cols,
col_data,
dml_cte_rvar, [lname_to_id_rvar],
props_only,
target_is_scalar,
iterator_cte,
ctx=ctx)
toplevel.ctes.append(data_cte)
data_select = pgast.SelectStmt(
target_list=[
pgast.ResTarget(val=pgast.ColumnRef(
name=[data_cte.name, pgast.Star()]))
],
from_clause=[pgast.RangeVar(relation=data_cte)])
# Inserting rows into the link table may produce cardinality
# constraint violations, since the INSERT into the link table
# is executed in the snapshot where the above DELETE from
# the link table is not visible. Hence, we need to use
# the ON CONFLICT clause to resolve this.
conflict_cols = ['std::source', 'std::target', 'ptr_item_id']
conflict_inference = []
conflict_exc_row = []
for col in conflict_cols:
conflict_inference.append(pgast.ColumnRef(name=[col]))
conflict_exc_row.append(pgast.ColumnRef(name=['excluded', col]))
conflict_data = pgast.SelectStmt(
target_list=[
pgast.ResTarget(val=pgast.ColumnRef(
name=[data_cte.name, pgast.Star()]))
],
from_clause=[pgast.RangeVar(relation=data_cte)],
where_clause=astutils.new_binop(
lexpr=pgast.ImplicitRowExpr(args=conflict_inference),
rexpr=pgast.ImplicitRowExpr(args=conflict_exc_row),
op='='))
cols = [pgast.ColumnRef(name=[col]) for col in tab_cols]
updcte = pgast.CommonTableExpr(
name=ctx.env.aliases.get(hint='i'),
query=pgast.InsertStmt(
relation=target_rvar,
select_stmt=data_select,
cols=cols,
on_conflict=pgast.OnConflictClause(
action='update',
infer=pgast.InferClause(index_elems=conflict_inference),
target_list=[
pgast.MultiAssignRef(columns=cols, source=conflict_data)
]),
returning_list=[
pgast.ResTarget(val=pgast.ColumnRef(name=[pgast.Star()]))
]))
pathctx.put_path_value_rvar(updcte.query,
path_id.ptr_path(),
target_rvar,
env=ctx.env)
# Record the effect of this insertion in the relation overlay
# context to ensure that the RETURNING clause potentially
# referencing this link yields the expected results.
overlays = ctx.env.rel_overlays[ptrcls.shortname]
overlays.append(('union', updcte))
toplevel.ctes.append(updcte)
return data_cte
def init_dml_stmt(
ir_stmt: irast.MutatingStmt, dml_stmt: pgast.DML, *,
ctx: context.CompilerContextLevel,
parent_ctx: context.CompilerContextLevel) \
-> typing.Tuple[pgast.Query, pgast.CommonTableExpr,
pgast.CommonTableExpr]:
"""Prepare the common structure of the query representing a DML stmt.
:param ir_stmt:
IR of the statement.
:param dml_stmt:
SQL DML node instance.
:return:
A (*wrapper*, *dml_cte*, *range_cte*) tuple, where *wrapper* the
the wrapping SQL statement, *dml_cte* is the CTE representing the
SQL DML operation in the main relation of the Object, and
*range_cte* is the CTE for the subset affected by the statement.
*range_cte* is None for INSERT statmenets.
"""
wrapper = ctx.rel
clauses.init_stmt(ir_stmt, ctx, parent_ctx)
target_ir_set = ir_stmt.subject
dml_stmt.relation = dbobj.range_for_set(ir_stmt.subject,
include_overlays=False,
env=ctx.env)
pathctx.put_path_value_rvar(dml_stmt,
target_ir_set.path_id,
dml_stmt.relation,
env=ctx.env)
dml_stmt.path_scope.add(target_ir_set.path_id)
dml_cte = pgast.CommonTableExpr(query=dml_stmt,
name=ctx.env.aliases.get(hint='m'))
if isinstance(ir_stmt, (irast.UpdateStmt, irast.DeleteStmt)):
# UPDATE and DELETE operate over a range, so generate
# the corresponding CTE and connect it to the DML query.
range_cte = get_dml_range(ir_stmt, dml_stmt, ctx=ctx)
range_rvar = pgast.RangeVar(
relation=range_cte,
alias=pgast.Alias(aliasname=ctx.env.aliases.get(hint='range')))
relctx.pull_path_namespace(target=dml_stmt, source=range_rvar, ctx=ctx)
# Auxillary relations are always joined via the WHERE
# clause due to the structure of the UPDATE/DELETE SQL statments.
id_col = common.edgedb_name_to_pg_name('std::id')
dml_stmt.where_clause = astutils.new_binop(
lexpr=pgast.ColumnRef(
name=[dml_stmt.relation.alias.aliasname, id_col]),
op=ast.ops.EQ,
rexpr=pathctx.get_rvar_path_identity_var(range_rvar,
target_ir_set.path_id,
env=ctx.env))
# UPDATE has "FROM", while DELETE has "USING".
if hasattr(dml_stmt, 'from_clause'):
dml_stmt.from_clause.append(range_rvar)
else:
dml_stmt.using_clause.append(range_rvar)
else:
range_cte = None
# Due to the fact that DML statements are structured
# as a flat list of CTEs instead of nested range vars,
# the top level path scope must be empty. The necessary
# range vars will be injected explicitly in all rels that
# need them.
ctx.path_scope.clear()
pathctx.put_path_value_rvar(dml_stmt,
ir_stmt.subject.path_id,
dml_stmt.relation,
env=ctx.env)
dml_rvar = pgast.RangeVar(
relation=dml_cte,
alias=pgast.Alias(aliasname=parent_ctx.env.aliases.get('d')))
relctx.include_rvar(wrapper,
dml_rvar,
ir_stmt.subject.path_id,
aspect='value',
ctx=ctx)
pathctx.put_path_bond(wrapper, ir_stmt.subject.path_id)
return wrapper, dml_cte, dml_rvar, range_cte
def process_insert_body(ir_stmt: irast.MutatingStmt, wrapper: pgast.Query,
insert_cte: pgast.CommonTableExpr,
insert_rvar: pgast.BaseRangeVar, *,
ctx: context.CompilerContextLevel) -> None:
"""Generate SQL DML CTEs from an InsertStmt IR.
:param ir_stmt:
IR of the statement.
:param wrapper:
Top-level SQL query.
:param insert_cte:
CTE representing the SQL INSERT to the main relation of the Object.
"""
cols = [pgast.ColumnRef(name=['std::__type__'])]
select = pgast.SelectStmt(target_list=[])
values = select.target_list
# The main INSERT query of this statement will always be
# present to insert at least the std::id and std::__type__
# links.
insert_stmt = insert_cte.query
insert_stmt.cols = cols
insert_stmt.select_stmt = select
if ir_stmt.parent_stmt is not None:
iterator_set = ir_stmt.parent_stmt.iterator_stmt
else:
iterator_set = None
if iterator_set is not None:
with ctx.substmt() as ictx:
ictx.path_scope = ictx.path_scope.new_child()
ictx.path_scope[iterator_set.path_id] = ictx.rel
clauses.compile_iterator_expr(ictx.rel, iterator_set, ctx=ictx)
ictx.rel.path_id = iterator_set.path_id
pathctx.put_path_bond(ictx.rel, iterator_set.path_id)
iterator_cte = pgast.CommonTableExpr(
query=ictx.rel, name=ctx.env.aliases.get('iter'))
ictx.toplevel_stmt.ctes.append(iterator_cte)
iterator_rvar = dbobj.rvar_for_rel(iterator_cte, env=ctx.env)
relctx.include_rvar(select,
iterator_rvar,
path_id=ictx.rel.path_id,
ctx=ctx)
iterator_id = pathctx.get_path_identity_var(select,
iterator_set.path_id,
env=ctx.env)
else:
iterator_cte = None
iterator_id = None
values.append(
pgast.ResTarget(val=pgast.SelectStmt(
target_list=[pgast.ResTarget(val=pgast.ColumnRef(name=['id']))],
from_clause=[
pgast.RangeVar(relation=pgast.Relation(name='objecttype',
schemaname='edgedb'))
],
where_clause=astutils.new_binop(
op=ast.ops.EQ,
lexpr=pgast.ColumnRef(name=['name']),
rexpr=pgast.Constant(val=ir_stmt.subject.scls.shortname)))))
external_inserts = []
tuple_elements = []
parent_link_props = []
with ctx.newrel() as subctx:
subctx.rel = select
subctx.rel_hierarchy[select] = insert_stmt
subctx.expr_exposed = False
subctx.shape_format = context.ShapeFormat.FLAT
if iterator_cte is not None:
subctx.path_scope = ctx.path_scope.new_child()
subctx.path_scope[iterator_cte.query.path_id] = select
# Process the Insert IR and separate links that go
# into the main table from links that are inserted into
# a separate link table.
for shape_el in ir_stmt.subject.shape:
rptr = shape_el.rptr
ptrcls = rptr.ptrcls.material_type()
if (ptrcls.is_link_property()
and rptr.source.path_id != ir_stmt.subject.path_id):
parent_link_props.append(shape_el)
continue
ptr_info = pg_types.get_pointer_storage_info(
ptrcls,
schema=subctx.env.schema,
resolve_type=True,
link_bias=False)
props_only = False
# First, process all local link inserts.
if ptr_info.table_type == 'ObjectType':
props_only = True
field = pgast.ColumnRef(name=[ptr_info.column_name])
cols.append(field)
insvalue = insert_value_for_shape_element(insert_stmt,
wrapper,
ir_stmt,
shape_el,
iterator_id,
ptr_info=ptr_info,
ctx=subctx)
tuple_el = astutils.tuple_element_for_shape_el(shape_el, field)
tuple_elements.append(tuple_el)
values.append(pgast.ResTarget(val=insvalue))
ptr_info = pg_types.get_pointer_storage_info(ptrcls,
resolve_type=False,
link_bias=True)
if ptr_info and ptr_info.table_type == 'link':
external_inserts.append((shape_el, props_only))
if iterator_cte is not None:
cols.append(pgast.ColumnRef(name=['__edb_token']))
values.append(pgast.ResTarget(val=iterator_id))
pathctx.put_path_identity_var(insert_stmt,
iterator_set.path_id,
cols[-1],
force=True,
env=subctx.env)
pathctx.put_path_bond(insert_stmt, iterator_set.path_id)
toplevel = ctx.toplevel_stmt
toplevel.ctes.append(insert_cte)
# Process necessary updates to the link tables.
for shape_el, props_only in external_inserts:
process_link_update(ir_stmt,
shape_el,
props_only,
wrapper,
insert_cte,
iterator_cte,
ctx=ctx)
if parent_link_props:
prop_elements = []
with ctx.newscope() as scopectx:
scopectx.rel = wrapper
for shape_el in parent_link_props:
rptr = shape_el.rptr
scopectx.path_scope[rptr.source.path_id] = wrapper
pathctx.put_path_rvar_if_not_exists(wrapper,
rptr.source.path_id,
insert_rvar,
aspect='value',
env=scopectx.env)
dispatch.compile(shape_el, ctx=scopectx)
tuple_el = astutils.tuple_element_for_shape_el(shape_el, None)
prop_elements.append(tuple_el)
valtuple = pgast.TupleVar(elements=prop_elements, named=True)
pathctx.put_path_value_var(wrapper,
ir_stmt.subject.path_id,
valtuple,
force=True,
env=ctx.env)
def cte_for_query(rel: pgast.Query, *,
env: context.Environment) -> pgast.CommonTableExpr:
return pgast.CommonTableExpr(
query=rel, alias=pgast.Alias(aliasname=env.aliases.get(rel.name)))
def compile_GroupStmt(stmt: irast.GroupStmt, *,
ctx: context.CompilerContextLevel) -> pgast.Query:
parent_ctx = ctx
with parent_ctx.substmt() as ctx:
clauses.init_stmt(stmt, ctx=ctx, parent_ctx=parent_ctx)
group_path_id = stmt.group_path_id
# Process the GROUP .. BY part into a subquery.
with ctx.subrel() as gctx:
gctx.expr_exposed = False
gquery = gctx.rel
pathctx.put_path_bond(gquery, group_path_id)
if stmt.path_scope:
ctx.path_scope.update(
{path_id: gquery
for path_id in stmt.path_scope.paths})
relctx.update_scope(stmt.subject, gquery, ctx=gctx)
stmt.subject.path_scope = None
clauses.compile_output(stmt.subject, ctx=gctx)
subj_rvar = pathctx.get_path_rvar(gquery,
stmt.subject.path_id,
aspect='value',
env=gctx.env)
relctx.ensure_bond_for_expr(stmt.subject,
subj_rvar.query,
ctx=gctx)
group_paths = set()
part_clause = []
for expr in stmt.groupby:
with gctx.new() as subctx:
partexpr = dispatch.compile(expr, ctx=subctx)
part_clause.append(partexpr)
group_paths.add(expr.path_id)
# Since we will be computing arbitrary expressions
# based on the grouped sets, it is more efficient
# to compute the "group bond" as a small unique
# value than it is to use GROUP BY and aggregate
# actual id values into an array.
#
# To achieve this we use the first_value() window
# function while using the GROUP BY clause as
# a partition clause. We use the id of the first
# object in each partition if GROUP BY input is
# a ObjectType, otherwise we generate the id using
# row_number().
if isinstance(stmt.subject.scls, s_objtypes.ObjectType):
first_val = pathctx.get_path_identity_var(gquery,
stmt.subject.path_id,
env=ctx.env)
else:
with ctx.subrel() as subctx:
wrapper = subctx.rel
gquery_rvar = dbobj.rvar_for_rel(gquery, env=ctx.env)
wrapper.from_clause = [gquery_rvar]
relctx.pull_path_namespace(target=wrapper,
source=gquery_rvar,
ctx=subctx)
new_part_clause = []
for i, expr in enumerate(part_clause):
path_id = stmt.groupby[i].path_id
pathctx.put_path_value_var(gquery,
path_id,
expr,
force=True,
env=ctx.env)
output_ref = pathctx.get_path_value_output(gquery,
path_id,
env=ctx.env)
new_part_clause.append(
dbobj.get_column(gquery_rvar, output_ref))
part_clause = new_part_clause
first_val = pathctx.get_rvar_path_identity_var(
gquery_rvar, stmt.subject.path_id, env=ctx.env)
gquery = wrapper
pathctx.put_path_bond(gquery, group_path_id)
group_id = pgast.FuncCall(
name=('first_value', ),
args=[first_val],
over=pgast.WindowDef(partition_clause=part_clause))
pathctx.put_path_identity_var(gquery,
group_path_id,
group_id,
env=ctx.env)
pathctx.put_path_value_var(gquery,
group_path_id,
group_id,
env=ctx.env)
group_cte = pgast.CommonTableExpr(query=gquery,
name=ctx.env.aliases.get('g'))
group_cte_rvar = dbobj.rvar_for_rel(group_cte, env=ctx.env)
# Generate another subquery contaning distinct values of
# path expressions in BY.
with ctx.subrel() as gvctx:
gvquery = gvctx.rel
relctx.include_rvar(gvquery, group_cte_rvar, ctx=gvctx)
pathctx.put_path_bond(gvquery, group_path_id)
for group_set in stmt.groupby:
dispatch.compile(group_set, ctx=gvctx)
path_id = group_set.path_id
if path_id.is_objtype_path():
pathctx.put_path_bond(gvquery, path_id)
gvquery.distinct_clause = [
pathctx.get_path_identity_var(gvquery,
group_path_id,
env=ctx.env)
]
for path_id, aspect in list(gvquery.path_rvar_map):
if path_id not in group_paths and path_id != group_path_id:
gvquery.path_rvar_map.pop((path_id, aspect))
for path_id, aspect in list(gquery.path_rvar_map):
if path_id in group_paths:
gquery.path_rvar_map.pop((path_id, aspect))
gquery.path_namespace.pop((path_id, aspect), None)
gquery.path_outputs.pop((path_id, aspect), None)
groupval_cte = pgast.CommonTableExpr(query=gvquery,
name=ctx.env.aliases.get('gv'))
groupval_cte_rvar = dbobj.rvar_for_rel(groupval_cte, env=ctx.env)
o_stmt = stmt.result.expr
# process the result expression;
with ctx.subrel() as selctx:
selquery = selctx.rel
outer_id = stmt.result.path_id
inner_id = o_stmt.result.path_id
relctx.include_rvar(selquery,
groupval_cte_rvar,
group_path_id,
aspect='identity',
ctx=ctx)
for path_id in group_paths:
selctx.path_scope[path_id] = selquery
pathctx.put_path_rvar(selquery,
path_id,
groupval_cte_rvar,
aspect='value',
env=ctx.env)
selctx.group_by_rels = selctx.group_by_rels.copy()
selctx.group_by_rels[group_path_id, stmt.subject.path_id] = \
group_cte
selquery.view_path_id_map = {outer_id: inner_id}
selquery.ctes.append(group_cte)
sortoutputs = []
selquery.ctes.append(groupval_cte)
clauses.compile_output(o_stmt.result, ctx=selctx)
# The WHERE clause
selquery.where_clause = astutils.extend_binop(
selquery.where_clause,
clauses.compile_filter_clause(o_stmt.where, ctx=selctx))
for ir_sortexpr in o_stmt.orderby:
alias = ctx.env.aliases.get('s')
sexpr = dispatch.compile(ir_sortexpr.expr, ctx=selctx)
selquery.target_list.append(
pgast.ResTarget(val=sexpr, name=alias))
sortoutputs.append(alias)
if not gvquery.target_list:
# No values were pulled from the group-values rel,
# we must remove the DISTINCT clause to prevent
# a syntax error.
gvquery.distinct_clause[:] = []
query = ctx.rel
result_rvar = dbobj.rvar_for_rel(selquery, lateral=True, env=ctx.env)
relctx.include_rvar(query, result_rvar, path_id=outer_id, ctx=ctx)
for rt in selquery.target_list:
if rt.name is None:
rt.name = ctx.env.aliases.get('v')
if rt.name not in sortoutputs:
query.target_list.append(
pgast.ResTarget(val=dbobj.get_column(result_rvar, rt.name),
name=rt.name))
for i, expr in enumerate(o_stmt.orderby):
sort_ref = dbobj.get_column(result_rvar, sortoutputs[i])
sortexpr = pgast.SortBy(node=sort_ref,
dir=expr.direction,
nulls=expr.nones_order)
query.sort_clause.append(sortexpr)
# The OFFSET clause
if o_stmt.offset:
with ctx.new() as ctx1:
ctx1.clause = 'offsetlimit'
ctx1.expr_exposed = False
query.limit_offset = dispatch.compile(o_stmt.offset, ctx=ctx1)
# The LIMIT clause
if o_stmt.limit:
with ctx.new() as ctx1:
ctx1.clause = 'offsetlimit'
ctx1.expr_exposed = False
query.limit_count = dispatch.compile(o_stmt.limit, ctx=ctx1)
clauses.fini_stmt(query, ctx, parent_ctx)
return query