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This section will provide an overview of database components, relational databases, table keys, table relationships, database queries and common database vendors. A database is a collection of data that can be sorted and searched using search algorithms. Databases are useful for storing, manipulating, managing and querying large amounts of data. Database components are referred to as database objects and are each stored separately within the database. In a database structure, data values are stored in tables. A table can contain data such as personnel information, product inventories, customer lists, sales figures and so forth. A database can consist of multiple tables, depending on the complexity of the data being stored. A field is a category of information in a table. Each column in a table represents a field. A record is a collection of information consisting of one or more related fields about a specific entity, such as a person, product or event. Each row in a table represents a record. A relational database contains multiple tables of information that are related through common fields. By contrast, a non-relational database consists of multiple tables of information that are not related through common fields. When multiple tables have a field in common, they can be joined to form a relationship to access the table data as needed. A table relationship is established by matching data in key fields between two database tables. Usually, the fields have the same name in both tables; however, the names can be different. In any given relationship, the table in which the common field is the primary key is called the primary table. The other table in the relationship is called the related table. The common field in the related table is called the foreign key. A database table can have only one primary key. A table relationship is established by matching data in key fields between two database tables. Usually, the fields have the same name in both tables; however, the names can be different. In any given relationship, the table in which the common field is the primary key is called the primary table. The other table in the relationship is called the related table. The common field in the related table is called the foreign key. A database table can have only one primary key. A table relationship is established by matching data in key fields between two database tables. Usually, the fields have the same name in both tables; however, the names can be different. In any given relationship, the table in which the common field is the primary key is called the primary table. The other table in the relationship is called the related table. The common field in the related table is called the foreign key. A database table can have only one primary key.