Relational Database Management Systems and Database Tables
RDBMS is an acronym for Relational Database Management System. The data in RDBMS is stored in database objects called tables. The database tables are the primary data storage for every RDBMS and essentially they are collections of related data entries. For example a table called Users might store information about many persons, and each entry in this table will represent one unique user. Even though all user entries in the Users table are unique, they are related in the sense that they describe similar objects.
Each database table consists of columns and rows. Each table column defines the type of data stored in it, and this data type is valid for all rows in this table. A table row is a collection of data having 1 entry for each column in this particular table.
RDBMS store the data into group of tables, which might or might not be related by common fields (database table columns). RDBMS also provide relational operators to insert/update/delete information stored into the database tables.
MS SQL Server, DB2, Oracle and MySQL are all Relational Database Management Systems.
I'll be using the RDBMS and database words interchangeably throughout this SQL Tutorial, so whenever I use the word database I mean RDBMS and the other way around.