1.Relational Databases:  Ø   In  RDBMS , data is stored in tables , in form of rows and columns, where a row represent the record of the data and column represents the attributes of the record. Ø   Relational database model has two main terminologies called instance and schema. o    Instance is a table with rows or columns o    Schema specifies the structure like name of the relation, type of each column and name. Ø   For example, a student table stores the records of various students, a row of this table represents the record of a single student and the column represents the attributes of the record such as student id, name, age, address etc. ID      Name          Age      Address ---     ---------     ----     -------- 101     Obaid          ...