A relational database is a collection of data organized in two-dimensional tables consisting of named columns and rows. Each table represents the mathematical concept of a relation as defined in set theory. In set theory, columns are known as attributes and rows are known as tuples. The operations that may be performed on tables are similarly based on manipulation of relations to produce new relations, usually referred to as queries or views.
Relational databases differ from non-relational databases in that the database user is not aware of system dependencies that may be stored within the data. No knowledge of the underlying database is required; data can be queried and updated using standard languages (these languages together make up SQL) that produce a consistent result. SQL Server databases are relational.
An RDBMS is responsible for:
- Storing and making data available in tables.
- Maintaining the relationships between tables in the database.
- Ensuring the integrity of data, by making sure that rules governing the data values and defining the relationships between tables are not violated.
- Recovering all data to a point of known consistency in case of a system failure.
Temas Relacionados:
