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 ...

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 ...

One of the principles within relational theory is that each entity’s row or tuple be uniquely identifiable. This means the defined structure includes some combination of attributes whose populated ...

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 about ...

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.

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 with a ...

Databases are used in many different settings, for different purposes. For example, libraries use databases to keep track of which books are available and which are out on loan. Schools may use ...