Feature support

Which sqlc features and query commands the plugin supports.

Macros

Every sqlc macro is supported (sqlc.arg, sqlc.narg, sqlc.embed, sqlc.slice).

sqlc.slice is for the SQLite drivers, where a list cannot be passed to the IN operator: the generated function expands the placeholder at call time, one ? per element, and an empty sequence matches no rows. Because the SQL is built per call, it cannot be used with prepared statements. On PostgreSQL the macro is not needed - use = ANY($1::type[]), which accepts the sequence directly.

Query commands

The supported query annotations depend on the driver:

Command	aiosqlite	sqlite3	asyncpg	psycopg_async
`:one`	yes	yes	yes	yes
`:many`	yes	yes	yes	yes
`:exec`	yes	yes	yes	yes
`:execresult`	yes	yes	yes	yes
`:execrows`	yes	yes	yes	yes
`:execlastid`	yes	yes	no	no
`:copyfrom`	no	no	yes	yes

See Writing queries for what each command generates.

:execlastid relies on a last-inserted-row id, which PostgreSQL does not provide; use a RETURNING clause with :one instead. :copyfrom maps to PostgreSQL’s bulk COPY protocol (copy_records_to_table on asyncpg, cursor.copy() on psycopg), which the SQLite drivers have no equivalent for.

Prepared queries

Coming from sqlc’s Go workflow you might look for an emit_prepared_queries equivalent. There is none, on purpose: every supported Python driver already prepares statements automatically, so the generated code gets prepared-query performance without any extra codegen. What differs per driver is when a query gets prepared and which knob controls it:

asyncpg prepares every query it runs and keeps it in a per-connection LRU statement cache (100 entries by default). Tune it at connect time:
```
conn = await asyncpg.connect(
    dsn,
    statement_cache_size=200,  # default 100; 0 disables the cache
)
```
psycopg prepares a query server-side once it has been executed more than prepare_threshold times on the connection - with the default of 5, the sixth execution is the first prepared one. Set it to 0 to prepare from the first execution, or None to never prepare:
```
conn = await psycopg.AsyncConnection.connect(dsn, prepare_threshold=0)
```
sqlite3 / aiosqlite expose no explicit prepare API, but the sqlite3 module compiles each statement once and reuses it through an internal per-connection cache (128 entries by default). Raise it with the cached_statements argument of connect() if you have more distinct queries than that.

Behind PgBouncer in transaction-pooling mode, server-side prepared statements belong to a connection you do not control. Disable them there: statement_cache_size=0 for asyncpg, prepare_threshold=None for psycopg.

Not supported

:batch* commands (:batchexec, :batchmany, :batchone) are not supported and likely never will be.
psycopg2 and mysql drivers are not currently supported; Psycopg 3 is, via the async psycopg_async driver.

Type mappings