Two. Relational data model
Four. Interface of python with an sql database
Introduction of Database Management System (DBMS):
Four. Object Oriented Model:
Before we proceed further, let's discuss about some aspects of Conceptual Data Model
Basic Terminology of ER Model:
Commonly used datatype in SQL:
Two. Character String Type:
Four. Date and Time Type:
KEYS IN TABLE (PLEASE READ IN ORDER OF NUMBER)
Structured Query Language:
SQL (STRUCTURED QUERY LANGUAGE) COMMANDS
One. Primary Key Constraints:
Let's learn with the help of example:
Three. NOT NULL Constraints : Which never accept NULL values
DDL (Data Definition Language) Commands:
Add a column to the table:
Drop a column from the table:
Five. Add/drop constraints/column: We can add/drop constraints in a table using alter command.
DML (Data Manipulation Language) Commands:
In clause and not in clause:
Order by Clause: It is used to sort the output of the select statement in ascending or descending order.
One. underscore: It is used to match one character.
Five. Count: it is used to count number of values in a column.