pkg/exec

The exec package handles query execution and row scanning.

DB Interface

type DB interface {
    Exec(ctx context.Context, sql string, arguments ...any) (pgconn.CommandTag, error)
    Query(ctx context.Context, sql string, args ...any) (pgx.Rows, error)
    QueryRow(ctx context.Context, sql string, args ...any) pgx.Row
}

Satisfied by pgx.Conn, *pgxpool.Pool, and pgx.Tx.

Scanner Interface

Your scanner struct must implement:

type Scanner[C ColumnAlias] interface {
    GetTarget(col string) func() any
}

GetTarget returns a function that provides a pointer to the struct field for scanning. The executor calls this for each column in the result set.

Query Methods

These methods are available on every Table:

Query (multiple rows)

scanners, err := Users.Query(ctx, db, selectQuery)
// Returns []*UsersScanner

QueryRow (single row)

scanner, err := Users.QueryRow(ctx, db, selectQuery)
// Returns *UsersScanner

With Relations

scanners, err := Users.Query(ctx, db, query,
    exec.WithRelations(relationLoader1, relationLoader2),
)

Execution Flow

1. Build SQL from query
2. Execute via db.Query() or db.QueryRow()
3. For each row, create a new Scanner via the factory function
4. Call GetTarget(col) for each column to get scan destinations
5. Scan row into the scanner
6. After all rows, load relations (if any)
7. Return populated scanners