Learn how to add and remove Primary Keys from an Access database table. The primary key's purpose is to promptly associate data from multiple tables and combine that data.

Imagine each squad member as a primary key, representing a unique identifier within a database table. Similar to how each squad member has a unique player ID, a primary key in SQL ensures that each ...

SQLite will assume an explicitly named integer primary key is just an alias for the rowid if the type is spelled out as "INTEGER" rather than "INT." I can simply change my create table statement as ...

Remember, the primary key in the Authors table is a complex key based on both the first and last name fields. Therefore, you must add both fields to the Books table.

The UPDATE rule controls data modification such that a foreign key value cannot be updated to a value that does not correspond to a primary key value in the parent table. There are, however, two ways ...

When working on a multidimensional design, every fact table within scope should be handled with care. In an ideal world, each low-level fact table represents the metrics related to a business event.

There are two attributes you can put on your entity class properties: one is a convenience, the other is essential, and both are required when the primary key for a table consists of two columns. When ...

Every JPA entity has a primary key, but some entities have more than one value as their primary key. In this case, you need to use a composite key. This Java tip introduces you to using composite ...