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.

Some database designers may feel that it’s OK to arbitrarily assign all dimensional foreign keys as part of a fact’s primary key even when one or more do not actually contribute to the fact table’s ...

The column (field) in a relational database that uniquely identifies the row in the table. For example, account number is often a primary key. A "composite primary key" or "super key" is made up ...

Generated keys can be a useful tool in creating logical database designs, but they can be easily over-used. The designer must consider whether the business truly wishes to drive a function that ...

To link databases together to create a relational database, a foreign key is used. A foreign key is a field in one table that is linked to the primary key in another table.

All documents in a MongoDB collection have a primary key dubbed _id . This field is automatically assigned to a document upon insert, so there’s rarely a need to provide it. What’s interesting ...

Duplicate and Ignore on MySQL Inserts. MySQL table primary keys and unique indexes prevent multiple rows with the same index from being added to the table. If you try to insert a duplicate row ...

Mitigating the Cosmos DB vulnerability In addition to replacing their primary read-write keys, Cosmos DB users should also review and restrict the network exposure of their databases.