A relational database consists of many tables, and these may be related to each other using keys and foreign keys. Each table is organised as rows and columns; each row represents a collection of data about a single entity, with its attributes identified by the column names. The database will typically be normalised such that related pieces of data are packaged up into their own tables - rather than repeating the same data over and over. These data in the new table are then referenced in the original table using a foreign key that corresponds to a key in the new table.
A relational database must maintain entity integrity (data being stored correctly) and referential integrity (relationships between entities being correct).
Indexes are used to give fast access to the database, and are specified as combinations of different column names that are referred to when querying the database.
A relational database must maintain entity integrity (data being stored correctly) and referential integrity (relationships between entities being correct).
Indexes are used to give fast access to the database, and are specified as combinations of different column names that are referred to when querying the database.