Managing Tables

Boolean: Used when TRUE, FALSE or unknown. It can take NULL values. Character: PostgreSQL provides three types of character data: CHAR(n), VARCHAR(n), and TEXT. CHAR(n) is a space-filled fixed-length character. If you add a string expression that is shorter than the column’s length, PostgreSQL fills in the blanks. If you add a string expression longer … Data Type

The syntax used to create a new table is as follows. column_constraint specifies the rules that the data stored in the column must follow.

The CREATE TABLE AS statement creates a new table and populates it with the queried data. The above query is executed to display the columns. As a result of the query, a table with 2 columns (rating, film_count) named film_reytingleri was created. Table data is taken from the film table.

Alter Table It is used to change the structure of an existing table. ALTER TABLE table_name action; – Adding columns – Delete a column – Change the data type of a column – Rename a column – Setting a default value for the column – Adding a constraint to a column – Rename a table … Alter, Rename, Drop, and Truncate Table

A temporary table is a transient table that exists for the duration of a database session. Temporary tables are automatically dropped at the end of a session or transaction. **A Temporary table is only visible to the session that created it. In other words, it is invisible to other sessions. PostgreSQL creates temporary tables in … Create Temporary Table

Copying a table completely, including both table structure and data The following expression is used for To copy the table structure without data, To copy some of the data from an existing table and create a new table; Example: As seen in the picture, the structure of the iletisim_backup table is the same as the … Copy table