When you are dropping a table that is referenced by another table, the object that immediately depends on the table being dropped is not the other table itself but the foreign key constraint defined on it. Here’s the description from the PostgreSQL 8.1 docs: DROP TABLE always removes any indexes, rules, triggers, and constraints that exist for the target table. Dropping your table is cascading through a constraint - Postgres is most likely bound up examining rows in that referencing table to determine what it needs to do about them. Refuse to drop the function if any objects depend on it. Automatically drop objects that depend on the function (such as operators or triggers), and in turn all objects that depend on those objects (see Section 5.13). (Emphasis mine.) The DROP INDEX CONCURRENTLY has some limitations:. CASCADE. RESTRICTrefuses to drop table if there is any object depends on it. First, the CASCADE option is not … We can put a list of tables after the DROP TABLE to remove multiple tables at once, each table separated by a comma. Also, you can include all inheriting tables when dropping the parent table using the CASCADE key word: A parent table cannot be dropped while any of its children remain. To speed things up you can drop your constraints first, and/or TRUNCATE the table you want to drop. However, to drop a table that is referenced by a view or a foreign-key constraint of another table, CASCADE must be specified. Hi I encountered something that puzzled me a bit. The first drop statement requires a cascade because there is a dependent little table that holds a foreign key constraint against the primary key column of the big table. Even though the TRUNCATE TABLE statement removes all … When you execute the DROP INDEX statement, PostgreSQL acquires an exclusive lock on the table and block other accesses until the index removal completes.. To force the command waits until the conflicting transaction completes before removing the index, you can use the CONCURRENTLY option.. CASCADE. I'm trying to drop a few tables with the "DROP TABLE" command but for a unknown reason, the program just "sits" and doesn't delete the table that I want it to in the database.. We can put a list of tables after the DROP TABLE to remove multiple tables at once, each table separated by a comma. CONCURRENTLY. The second drop statement does not require the cascade keyword because there is not a dependent foreign key constraint. RESTRICT. Is it expected that DROP table CASCADE drops this table and just the foreign key constraints but not the refering tables… PostgreSQL uses RESTRICT by default. I have 3 tables in the database: Product, Bill and Bill_Products which is used for referencing products in bills. Automatically drop objects that depend on the table (such as views). The DROP table removes any indexes, rules, triggers, and obstacles that are present for the target table. If you wish to remove a table and all of its descendants, one easy way is to drop the parent table with the CASCADE option. If you really want DELETE FROM some_table CASCADE; which means "remove all rows from table some_table", you can use TRUNCATE instead of DELETE and CASCADE is always supported. This is the default. However, if you want to use selective delete with a where clause, TRUNCATE is not good enough.. USE WITH CARE - This will drop all rows of all tables which have a foreign key constraint on some_table and all tables … However, if there are external dependencies, such as views, this is not possible without DROP CASCADE. The CASCADE option should be used with further consideration or you may potentially delete data from tables that you did not want.. 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