Layouts

Tapestry lets you control the layout of the query files i.e. how the generated SQL is organized in files. It supports two ways at present:

1. one-file-one-query: Each SQL query will be written to a separate file
2. one-file-all-queries: All SQL queries will be written to a single file

To configure this, you need to specify the query_output_layout key in the manifest. The default option if not specified is one-file-one-query.

Layout and queries[].output field

Users may specify output field for every query, which is the path where the generated SQL output will be written. If output is not specified, it's value is derived from the query id. This works well for the one-file-one-query layout.

Example:

[[queries]]
id = "artists_long_songs@genre*limit"
template = "artists_long_songs.sql.j2"
conds = [ "genre", "limit" ]

The derived value of output for the above will be artists_long_songs-genre-limit.sql.

But when the layout is one-file-all-queries, it's expected that the output field of all queries must be the same. Otherwise the manifest fails to validate. To avoid duplication, a related setting query_output_file is provided.

If layout = one-file-all-queries, it's recommended to set query_output_file and omit the output field for individual queries.

Example:

query_output_layout = "one-file-all-queries"
query_output_file = "queries.sql"

Tip: If layout = one-file-one-query, then you must not set query_output_file. Whether or not to set the output field for individual queries is up to you.

Layout and query tagging

Name tagging of queries is mandatory when layout is one-file-all-queries.

Why? (If you are curious): Name tags make parsing individual queries from a single SQL file much more straightforward. The status command relies on parsing of individual queries from a single output file.