MySQL

Information Systems Today (©2006 Prentice Hall)

MySQLMySQL

1CS3754 Class Note #8, 2013

1. Is an open-source relational database management system

2. Is fast and stable3. Is available as free software and as commercial

software4. Supports the majority of features considered important

by the database community5. Is a great tool for learning about databases


Installing MySQLInstalling MySQL

You can download MySQL from You can download MySQL from

www.mysql.com/down loadswww.mysql.com/down loads You can run MySQL on Linux on the You can run MySQL on Linux on the

computer system of our department computer system of our department by executing:by executing:

mysql –h stretch –u username -pmysql –h stretch –u username -p



Introduction to MySQL Introduction to MySQL MonitorMonitor

After logged in you can see what After logged in you can see what databases exist on the system by: databases exist on the system by: show database;show database;

You can select a database from the You can select a database from the listed database names by:listed database names by:use use databasenamedatabasename;;

After selecting a database, you can After selecting a database, you can see what table are in it by:see what table are in it by:show tables;show tables;



Introduction to MySQL Introduction to MySQL MonitorMonitor

You can get information on a particular table You can get information on a particular table by:by:

describe describe tablenametablename;; You can log out of the monitor by: \qYou can log out of the monitor by: \q You can get a help by: \hYou can get a help by: \h You can execute a file of commandsYou can execute a file of commands

When logged into the monitor by : Source When logged into the monitor by : Source filenamefilename When not logged into the monitorWhen not logged into the monitor by: by:

mysql –u username –p < filenamemysql –u username –p < filename

/* -u means username –p means login with password /* -u means username –p means login with password



Creating Databases and Creating Databases and TablesTables

Creating a database byCreating a database bycreate database create database databasenamedatabasename;;

Creating a table byCreating a table bycreate table create table tablename (table tablename (table definition) [type = table_type]definition) [type = table_type];;

Ex: create table deptEx: create table dept(deptID int not null auto_increment (deptID int not null auto_increment

primary key,primary key,Name varchar(30)) type=InnoDBName varchar(30)) type=InnoDB



Dropping Databases and Dropping Databases and TablesTables

Drop a database byDrop a database by

drop database drop database databasenamedatabasename;; Drop a table byDrop a table by

drop table drop table tablename;tablename;



Inserting, Deleting, and Inserting, Deleting, and Updating DataUpdating Data

Deleting by: Deleting by: delete from deptdelete from dept Inserting by: Inserting by:

insert into dept valuesinsert into dept values(42, ‘Finance’ ),(42, ‘Finance’ ),(128, ‘Research and Development’ );(128, ‘Research and Development’ );

Update by:Update by:

update employeeupdate employeeset job = ‘DBA’ set job = ‘DBA’ where employeeID = “6651’;where employeeID = “6651’;



Uploading data with Load Uploading data with Load Data InfileData Infile

The Load Data Infile command allows The Load Data Infile command allows you to bulk insert data from a text file you to bulk insert data from a text file into a single table without having to into a single table without having to write Insert statements.write Insert statements.

Example: Example:

load data local infile ‘dept_infile.txt’ load data local infile ‘dept_infile.txt’

into table dept;into table dept;

/* Local means the data file is on the /* Local means the data file is on the client machine not on the server. */client machine not on the server. */



Querying MySQLQuerying MySQL

Select columns from tables:Select columns from tables:

select * from dept;select * from dept;

select name, employeeID from employee;select name, employeeID from employee; Using joins to run queries over multiple tables:Using joins to run queries over multiple tables:

select employee.name as EmployeeName, dept.name as select employee.name as EmployeeName, dept.name as deptNamedeptName

from employee, deptfrom employee, dept

where employee.deptID = dept.deptID;where employee.deptID = dept.deptID;



Table Types in MySQLTable Types in MySQL ISAM, having replaced by MyISAMISAM, having replaced by MyISAM MyISAM as the default typeMyISAM as the default type

Offer very fast but not transaction-safe storageOffer very fast but not transaction-safe storage InnoDBInnoDB

Offer very fast and transaction-safe storageOffer very fast and transaction-safe storage Row-level lockingRow-level locking Supports for foreign keysSupports for foreign keys Tables are portable from systems to systemsTables are portable from systems to systems

BerkeleyDB (BDB) BerkeleyDB (BDB) Offer transaction-safe storage but slightly worse performance Offer transaction-safe storage but slightly worse performance

than InnoDBthan InnoDB MERGEMERGE

Used to treat multiple MyISAM tables as a single tableUsed to treat multiple MyISAM tables as a single table HEAPHEAP

Stored only in memory and need to be limited in sizeStored only in memory and need to be limited in size10CS3754 Class Note #8, 2013

MySQL

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