Name

yamltodb -- generate SQL statements to update a Postgres database to match the schema specified in a YAML file

Synopsis

yamltodb [option...] dbname [spec]

Description

yamltodb is a utility for generating SQL statements to update a Postgres database so that it will match the schema specified in an input YAML formatted specification file.

For example, given the input file shown under dbtoyaml, yamltodb, when run against a newly-created database, outputs the following SQL statements:

CREATE SCHEMA s1;
ALTER SCHEMA s1 OWNER TO bob;
GRANT ALL ON SCHEMA s1 TO bob;
GRANT ALL ON SCHEMA s1 TO alice;
CREATE TABLE t1 (
    c1 integer NOT NULL,
    c2 smallint,
    c3 boolean DEFAULT false,
    c4 text);
ALTER TABLE t1 OWNER TO alice;
CREATE TABLE s1.t2 (
    c21 integer NOT NULL,
    c22 character varying(16));
ALTER TABLE s1.t2 OWNER TO bob;
GRANT ALL ON TABLE s1.t2 TO bob;
GRANT SELECT ON TABLE s1.t2 TO PUBLIC;
GRANT INSERT, DELETE, UPDATE ON TABLE s1.t2 TO alice WITH GRANT OPTION;
GRANT INSERT ON TABLE s1.t2 TO carol;
ALTER TABLE t1 ADD CONSTRAINT t1_c2_check CHECK (c2 > 123);
ALTER TABLE t1 ADD CONSTRAINT t1_pkey PRIMARY KEY (c1);
ALTER TABLE s1.t2 ADD CONSTRAINT t2_pkey PRIMARY KEY (c21);
ALTER TABLE t1 ADD CONSTRAINT t1_c2_fkey FOREIGN KEY (c2) REFERENCES s1.t2 (c21);

Options

yamltodb accepts the following command-line arguments (in addition to the cmdargs):

dbname

Specifies the name of the database whose schema is to analyzed.

spec

Specifies the location of the YAML specification. If this is omitted or specified as a single or double dash, the specification is read from the program's standard input. However, if the --multiple-files option is used, that takes precedence.

Specifies that input should be taken from YAML specification files
present in a two-level (metadata) directory tree.  See `Multiple
File Output` under :doc:`dbtoyaml` for further details.

Compare only a schema matching `schema`.  By default, all schemas
are compared.  Multiple schemas can be compared by using multiple
:option:`-n` switches.

Wrap the generated statements in BEGIN/COMMIT. This ensures that
either all the statements complete successfully, or no changes are
applied.

Execute the generated statements against the database mentioned in
**dbname**.  This implies the :option:`--single-transaction`
option.

Generate SQL in reversion mode, that is, to undo the changes that
would normally be generated.  For example, if without this option,
the SQL would be a ``DROP TABLE``, the :option:`--revert` option
generates a ``CREATE TABLE`` with all the columns, constraints and
other objects associated with the table being dropped.

This option is experimental and currently has only been
implemented for schemas and sequences.

Examples

Given a YAML file named moviesdb.yaml, to generate SQL statements to update a database called mymovies:

yamltodb mymovies moviesdb.yaml

To generate the statements as above and immediately update mymovies:

yamltodb mymovies moviesdb.yaml | psql mymovies

or:

yamltodb --update mymovies moviesdb.yaml

To generate the statements directly from the output of dbtoyaml (against a different database), with statements enclosed in a single transaction, and save the statements in a file named mymovies.sql:

dbtoyaml devmovies | yamltodb -1 mymovies -o mymovies.sql