Introduction to Structured Query Language (SQL) — Chapter Summary

SQL is the language used

SQL is the language used to work with relational databases. It helps in creating tables, inserting records, updating values, deleting records, and ret

CREATE DATABASE makes a new database

CREATE DATABASE makes a new database, and CREATE TABLE defines its structure. The degree of a relation is the number of columns in the table.

CHAR(n) is fixed

CHAR(n) is fixed-length text, VARCHAR(n) is variable-length text, INT stores whole numbers, FLOAT stores decimal numbers, and DATE stores date values

Constraints such as NOT NULL

Constraints such as NOT NULL, UNIQUE, DEFAULT, PRIMARY KEY, and FOREIGN KEY control how data is stored and linked. By default, attributes can take NUL

A primary key uniquely identifies each

A primary key uniquely identifies each row. A foreign key refers to a primary key in another table. In STUDENT, RollNumber is the primary key and GUID