RDBMS Terminology

Relational Database Management System (R DBMS). Revise definitions related to database.

Database:- A database is a collection of tables, with related data.

Table:- A table is a matrix with data. A table in a database looks like a simple spreadsheet.

Column:- One column (data element) contains data of one and the same kind, for example the column postcode.

Row:- A row (tuple, entry or record) is a group of related data, for example the data of one subscription.

Redundancy:- Storing data twice, redundantly to make the system faster.

Primary key:- A primary key is unique. A key value can not occur twice in one table. With a key, you con find at most one row.

Foreign key:- A foreign key is the linking pin between two tables.

compound key:- A compound key (composite key) is a key that consists of multiple columns, because one column is not sufficiently unique.

Index:- An Index in a database resembles an index at the back of a book.

Referential integrity:- Referential Integrity makes sure that a foreign key value always points to an existing row.

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