SQL. intro to data

What us a database

Structured collection of data

What is DBMS and what are some example?

Database, oracle, ibm, Microsoft

What is a relational database

• rational data base consists of one or more table

What does a relational data base consist of

What type of of values can occur

Text

Integer

Primary key integer

What is ACID?

ACID refer to properties that assume your database is valid in case of errors a is atomicity, c is consistency, I is isolation, d is durability

How to create table?

CREATE TABLE groceries (id INTEGER PRIMARY KEY, name TEXT, quantity INTEGER );

how to insert values?

iNSERT INTO table VALUES(, "", );

how to select

SELECT (column or table ) FROM table

specific select

SELECT… FROM .. WHERE .. ORDER BY/GROUP BY

join table

SELECT - tableone. column, table2. column

FROM table 1

JOIN table 2

ON ID = ID

other options

ALL THESE COME AFTER SELECT

COUNT (*)

AVG

SUM

MAX

count order

select count (*) (always the whole table)

JOIN

WHERE

GROUP BY

HAVING

important to remember

important to remember 2

important remember 3

why use data base

• allows other applications of modify

• queries

• make sure the structure is right

• able to store a lot of dat

difference between excel and database