How to Modify Columns in PostgreSQL Views Without Dropping and Recreating Them?

Relaxing PostgreSQL's Grip on Views

Question:

How can I bypass PostgreSQL's strict control over column changes in views? I'd prefer to modify columns without having to drop and recreate the views every time.

Solution:

There are two approaches to achieve this:

Permanent Solution:

To eliminate the issue entirely, consider utilizing text or varchar/character varying data types without specifying a length. This will allow for seamless changes without affecting dependent views.

Alternatively, implement a CHECK constraint to enforce a maximum length:

ALTER TABLE monkey ADD CONSTRAINT monkey_name_len CHECK (length(name) < 101);

This constraint can be altered or removed without impacting views or triggering unnecessary data rewrites.

Detailed Explanation:

PostgreSQL views are not simply subquery aliases. They are implemented as tables with specialized rules, granting the flexibility to modify auxiliary attributes using ALTER TABLE. However, altering underlying data types requires dropping and recreating the view. This preserves data but may remove added attributes.

To change the underlying query in a view, utilize CREATE OR REPLACE VIEW. However, this is not possible for data type changes. Therefore, dropping and recreating the view is necessary to accommodate such modifications.

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