1.) A relational database management system oe RDBMS is a data bse that stores data in tables, so it can used in ralation to other stored databases.

2.) SQL is a language to operate databases. It allows the creation, deletion, modification, etc. of databases.

3.) A logical representation of the data for an establisment, using entities for categories of data and connections for union between entities.

4.) One-to-one      relationship: One data in a table has a connection with one and only one data in another table.
    One-to-many     relationship: One data in a table has a connection with one or more data in another table.
    Many-to-many    relationship: Multiple sets of data has mutiple connections with multiple sets of data in another table.

5.) Primary keys are used to uniquely identify a row in a database. No two rows should have the same primary key.