Code examples for Postgres

Remembering all the syntax for Postgres is hard, at least we find it hard to remember it all. Hopefully the examples below help you as much as they help us.
Alter Column Type
How to change a table column type in Postgres
Rename A Column
How to rename a table column in Postgres
Alter Column Default
How to change a column's default value in Postgres
Alter Column Nullable
How to change the nullable flag on a Postgres table column
CREATE INDEX examples
How to create an index on one (or many) columns in Postgres.
Alter Table Add Foreign Key
Adding a foreign key (otherwise known as a relation or association) to a Postgres table means adding a 'constraint'. These basic examples assume that the column type is correct, and any existing values match existing relation IDs in the target table.
Alter Table Drop Foreign Key / Constraint
Removing a foreign key (otherwise known as a relation or association) from a Postgres table. Note that after removing a relation, you might also want to remove any left over indexes.
Alter Table
A Postgres example for changing, adding, and removing columns for an existing table