I wrote a (recursive) function to delete any row based on its primary key. Can you give me steps to reproduce? However, to drop a table that is referenced by a view or a foreign-key constraint of another table, CASCADE must be specified. @arthur you could probably use some version of row -> json -> text to get it done, however, I've not gone that far. Since you have deleted the Employee table, if you retrieve the list of tables again, you can observe only one table in it. Cascade delete performance drop on bigger datasets, can this be caused by lack of indexing? Replacing characters using an expression in QGIS. The name (optionally schema-qualified) of the table to Grant's answer is partly wrong - Postgresql doesn't support CASCADE on DELETE queries. Refuse to drop the table if any objects depend on it. I came here a few months ago looking for an answer to the "CASCADE DELETE just once" question (originally asked over a decade ago!). ; Second, use the IF EXISTS option to conditionally delete schema only if it exists. Yeah, as others have said, there's no convenient 'DELETE FROM my_table ... CASCADE' (or equivalent). ; Third, use CASCADE to delete schema and all of its objects, and in turn, all objects that depend on those objects. Introduction to PostgreSQL DROP TABLE statement. However, to drop a table that is referenced by a Can a computer analyze audio quicker than real time playback? To achieve this in a general sense, see my table below, but it has some restrictions. Basically this function is passed in the schema, table name, and primary value (in string form), and it will start by finding any foreign keys on that table and makes sure data doesn't exist-- if it does, it recursively calls itsself on the found data. Stack Overflow for Teams is a private, secure spot for you and
rather than being concerned about "nasty shards" (cascading constraints will still be consistent), I'd be MORE concerned about the cascading not going far enough-- if the deleted records require further deleted records, then those constraints will need to be altered to ensure cascading as well. Please test it out and let me know how it works for you. It is faster if you have indexes on columns and data set is bigger than few records. Your function worked really well! (CASCADE will remove a dependent view entirely, but Is there any way I can perform a delete and tell Postgresql to cascade it just this once? How to create a LATEX like logo using any word at hand? DROP FOREIGN TABLE films, distributors; Compatibility This command conforms to the ISO/IEC 9075-9 (SQL/MED), except that the standard only allows one foreign table to be dropped per command, and apart from the IF EXISTS option, which is a PostgreSQL extension. To drop a column of a table, you use the DROP COLUMN clause in the ALTER TABLE statement as follows: ALTER TABLE table_name DROP COLUMN column_name; When you remove a column from a table, PostgreSQL will automatically remove all of the indexes and … Note: It's a little slow. I use this function VERY SPARINGLY anyway, I value my data too much to enable the cascading constraints on everything. DROP TABLE always removes any indexes, rules, triggers, and constraints that exist for the target table. @JoeLove what speed problem are you have? Safe Navigation Operator (?.) rows, without destroying the table, use DELETE. distributors: This command conforms to the SQL standard, except that the can be rolled back), although it is not fully isolated from other concurrent transactions, and has several other caveats. Oh no! In this article, we’ll discuss the PostgreSQL DELETE CASCADE and review some examples of … I have medium size databases for a multi-tenant CMS (clients all share the same tables). USE WITH CARE - This will drop all rows of all tables which have a foreign key constraint on some_table and all tables that have constraints on those tables, etc. dependents. The TRUNCATE TABLE statement is transaction-safe. DROP TABLE always removes any indexes, rules, triggers, and constraints that exist for the target table. Postgres supports CASCADE with TRUNCATE command: TRUNCATE some_table CASCADE; DROP TABLE always removes any indexes, rules, triggers, and constraints that exist for the target table. PostgreSQL will automatically delete all of its constraints and indexes, including the column while deleting a column from a table, and every drop column condition is separated by a comma (,).. We cannot delete those columns where the other objects depend on them and also used in other database objects like triggers, views, stored procedures, etc.. Drop the big and little table if they exists. Hey, @JoeLove. Provides an ASCII preview of the deletion target and its graph of To destroy two tables, films and but I just created your functions and then ran the following code: select recursively_delete('dallas.vendor',1094,false) After some debugging, I find that this dies right off the bat-- meaning, it seems like it's the first call to the function, not after doing multiple things. As with Joe Love's solution, it allows you to delete entire graphs of data as if all foreign key constraints in your database were momentarily set to CASCADE, but offers a couple additional features: I cannot comment Palehorse's answer so I added my own answer.
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