Closed
Description
Describe the use case
Add support for IF [NOT] EXISTS
for ADDDROP COLUMN
operations available on PostgreSQL
Databases / Backends / Drivers targeted
PostgreSQL
Example Use
The goal is to have automatically generated operations rewritable to add if_exists/if_not_exists
attributes, then rendered with postgres compiler.
@writer.rewrites(ops.AddColumnOp)
def add_column(autogen_context, _revision, op: ops.AddColumnOp):
op.if_not_exists = True
would generate following SQL
ALTER TABLE t ADD COLUMN IF NOT EXISTS c INTEGER;
Additional context
Spin-off of #524 for ADD/DROP COLUMN
Have a nice day!