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_tab = dbobj.range_for_ptrcls(ptrcls,
'>',
include_overlays=False,
env=ctx.env)
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, 'source', nullable=False),
op='=',
)
targets = []
for prop_el in ir_expr.shape:
ptrname = prop_el.rptr.ptrcls.get_shortname(ctx.env.schema)
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=ptrname.name,
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.get_shortname(ctx.env.schema).name))
toplevel.ctes.append(updcte)
def compile_UpdateStmt(stmt: irast.UpdateStmt, *,
ctx: context.CompilerContextLevel) -> pgast.Query:
parent_ctx = ctx
with parent_ctx.substmt() as ctx:
# Common DML bootstrap.
wrapper, update_cte, update_rvar, range_cte = dml.init_dml_stmt(
stmt, pgast.UpdateStmt(), parent_ctx=parent_ctx, ctx=ctx)
# Process UPDATE body.
dml.process_update_body(stmt, wrapper, update_cte, range_cte, ctx=ctx)
return dml.fini_dml_stmt(stmt,
wrapper,
update_cte,
update_rvar,
parent_ctx=parent_ctx,
ctx=ctx)