swh.core.db.db_utils module

swh.core.db.db_utils.stored_procedure(stored_proc)

decorator to execute remote stored procedure, specified as argument

Generally, the body of the decorated function should be empty. If it is not, the stored procedure will be executed first; the function body then.

swh.core.db.db_utils.jsonize(value)

Convert a value to a psycopg2 JSON object if necessary

swh.core.db.db_utils.execute_values_generator(cur, sql, argslist, template=None, page_size=100)

Execute a statement using SQL VALUES with a sequence of parameters. Rows returned by the query are returned through a generator. You need to consume the generator for the queries to be executed!

Parameters

• cur – the cursor to use to execute the query.

• sql – the query to execute. It must contain a single %s placeholder, which will be replaced by a VALUES list. Example: "INSERT INTO mytable (id, f1, f2) VALUES %s".

• argslist – sequence of sequences or dictionaries with the arguments to send to the query. The type and content must be consistent with template.

• template –

  the snippet to merge to every item in argslist to compose the query.

  • If the argslist items are sequences it should contain positional placeholders (e.g. "(%s, %s, %s)", or "(%s, %s, 42)” if there are constants value…).

  • If the argslist items are mappings it should contain named placeholders (e.g. "(%(id)s, %(f1)s, 42)").

  If not specified, assume the arguments are sequence and use a simple positional template (i.e. (%s, %s, ...)), with the number of placeholders sniffed by the first element in argslist.

• page_size – maximum number of argslist items to include in every statement. If there are more items the function will execute more than one statement.

• yield_from_cur – Whether to yield results from the cursor in this function directly.

After the execution of the function the cursor.rowcount property will not contain a total result.