bonus material on sql
Post on 04-Sep-2015
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Bonus Material: SQL
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collection of information
structure expressed in columns
data expressed in rows
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reduces wasted space
reduces repetition of information
enforces data integrity
maximizes efficiency
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structured query language
can be used to define db
used for manipulating data
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data definition create alter drop
data manipulation insert select update delete
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It is usually a good idea to SAVE your CREATE statements in case you ever need to recreate your tables.
Use ALTER statements judiciously and only after thorough consideration. ALTER can break normalization, and have other undesired results.
Use DROP statements even more carefully. Make sure you have a good backup first.
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create database
CREATE DATABASE database_name
create table
CREATE TABLE table_name ( column1 data_type, column2 data_type, etc... );
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CREATE TABLE students ( student_id int(9), first_name varchar(30), middle_name varchar(30), last_name varchar(30), address1 varchar(40), address2 varchar(40), city varchar(35), state char(2), zip int(5), zip4 int(4) );
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DROP TABLE table_name;
DROP TABLE students;
http://xkcd.com/327/ 10
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INSERT INTO table_name ( column1, column2, ... ) VALUES ( data_value1, data_value2, ... );
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INSERT INTO students ( column1, column2, ... ) VALUES ( data_value1, data_value2, ... );
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SELECT column_name(s)
FROM table_name(s)
WHERE condition(s);
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UPDATE table_name
SET column1=new_data_value1, column2=new_data_value2, ...
WHERE condition(s);
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DELETE FROM table_name
WHERE condition(s);
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