问题
How can I generate the DDL of a table programmatically on Postgresql? Is there a system query or command to do it? Googling the issue returned no pointers.
回答1:
Use pg_dump with this options:
pg_dump -U user_name -h host database -s -t table_or_view_names -f table_or_view_names.sql
Description:
-s or --schema-only : Dump only ddl / the object definitions (schema), without data.
-t or --table Dump : Dump only tables (or views or sequences) matching table
Examples:
-- dump each ddl table that elon build.
$ pg_dump -U elon -h localhost -s -t spacex -t tesla -t solarcity -t boring > companies.sql
Sorry if out of topic. Just wanna help who googling "psql dump ddl" and redirected to this thread.
回答2:
You can use the pg_dump command to dump the contents of the database (both schema and data). The --schema-only switch will dump only the DDL for your table(s).
回答3:
The answer is to check the source code for pg_dump and follow the switches it uses to generate the DDL. Somewhere inside the code there's a number of queries used to retrieve the metadata used to generate the DDL.
回答4:
Why would shelling out to psql not count as "programmatically?" It'll dump the entire schema very nicely.
Anyhow, you can get data types (and much more) from the information_schema (8.4 docs referenced here, but this is not a new feature):
=# select column_name, data_type from information_schema.columns
-# where table_name = 'config';
column_name | data_type
--------------------+-----------
id | integer
default_printer_id | integer
master_host_enable | boolean
(3 rows)
回答5:
Here is a good article on how to get the meta information from information schema, http://www.alberton.info/postgresql_meta_info.html.
回答6:
I saved 4 functions to mock up pg_dump -s behaviour partially. Based on \d+ metacommand. The usage would be smth alike:
\pset format unaligned
select get_ddl_t(schemaname,tablename) as "--" from pg_tables where tableowner <> 'postgres';
Of course you have to create functions prior.
Working sample here at rextester
来源：https://stackoverflow.com/questions/1884758/generate-ddl-programmatically-on-postgresql