Points to remember

Computer Science : Integrating Python with MySql and C++ : Data Manipulation Through SQL

Points to remember:

·        A database is an organized collection of data.

·        Users of database can be human users, other programs or applications

·        SQLite is a simple relational database system, which saves its data in regular data files.

·        Cursor is a control structure used to traverse and fetch the records of the database. All the SQL commands will be executed using cursor object only.

·        As data in a table might contain single or double quotes, SQL commands in Python are denoted as triple quoted string.

·        “Select” is the most commonly used statement in SQL

·        The SELECT Statement in SQL is used to retrieve or fetch data from a table in a database

·        The GROUP BY clause groups records into summary rows

·        The ORDER BY Clause can be used along with the SELECT statement to sort the data of specific fields in an ordered way

·        Having clause is used to filter data based on the group functions.

·        Where clause cannot be used along with ‘Group by’

·        The WHERE clause can be combined with AND, OR, and NOT operators

·        The ‘AND’ and ‘OR’ operators are used to filter records based on more than one condition

·        Aggregate functions are used to do operations from the values of the column and a single value is returned.

·        COUNT() function returns the number of rows in a table.

·        AVG() function retrieves the average of a selected column of rows in a table.

·        SUM() function retrieves the sum of a selected column of rows in a table.

·        MAX() function returns the largest value of the selected column.

·        MIN() function returns the smallest value of the selected column

·        sqlite_master is the master table which holds the key information about your database tables.

·        The path of a file can be either represented as ‘/’ or using ‘\\’ in Python. For example the path can be specified either as 'c:/pyprg/sql.csv', or c:\\pyprg\\sql.csv’.