MySQL

How to Truncate MySQL Table ?

Posted by 17 March, 2013 (0) Comment

In order to delete all records from a table use this command.

View Code MYSQL
TRUNCATE TABLE tbl_yourtable_name
Share
Categories : MySQL Tags :

MYSQL data manipulation language (DML) commands?

Posted by 31 December, 2010 (0) Comment

Data Manipulation Language

Data Manipulation Language (DML) statements are used for managing data within tables. Some commands of DML are:

View Code MYSQL
 
1. SELECT - retrieve data from the a database
2. INSERT - insert data into a table
3. UPDATE - updates existing data within a table
4. DELETE - deletes all records from a table, the space for the records remain
5. MERGE - UPSERT operation (insert or update)
6. CALL - call a PL/SQL or Java/php subprogram
7. LOCK TABLE - control concurrency
Share
Categories : MySQL Tags :

MYSQL data definition language (DDL) commands?

Posted by 31 December, 2010 (1) Comment

Data Definition Language (DDL)

DDL statements are used to define and modify the database structure of your tables or schema. When you execute a DDL statement, it takes effect immediately.
Some commands of DDL are:

View Code MYSQL
1. CREATE - to create table (objects) in the database
2. ALTER - alters the structure of the database
3. DROP - delete table from the database
4. TRUNCATE - remove all records from a table, including all spaces allocated for the records are removed
5. COMMENT - add comments to the data dictionary
6. RENAME - rename a table
Share
Categories : MySQL Tags :

How to backup and restore a MySQL database?

Posted by 31 December, 2010 (0) Comment

You can use mysqldump to create a simple backup of your database using the following syntax.

View Code MYSQL
mysqldump -u [username] -p [password] [databasename] > [backupfile.sql]
 
 
To Restore 
mysql -u [username] -p [password] [database_to_restore] < [backupfile]
Share
Categories : MySQL Tags :

MySql frequently used commands?

Posted by 17 September, 2010 (0) Comment

MySQL is one of the best and globally used database. It will be good to learn the basic commands in Mysql to work interactively with the website and database servers. It is an GPL software as well as paid version is available with support. MySQL uses Structured Query Language (SQL-pronounced sequel), here i have listed mostly used commands  for requesting information from a database.  Mysql sends each SQL statement that you issue to the server to be executed.  Because of its fast performance, reliability, ease of use, and versatility in working with programming languages NASA, FedEx, Yahoo other big php application are using mysql as backend.

This is a list of handy MySQL mysql-textboxs that I use time and time again. At the bottom are statements, clauses, and functions you can use in MySQL. Below that are PHP  functions you can use to interface with MySQL.

Below when you see # it means from the unix shell. When you see mysql> it means from a MySQL prompt after logging into MySQL.

To login (from unix shell) use -h only if needed.

# [mysql dir]/bin/mysql -h hostname -u root -p

Create a database on the sql server.

mysql> create database [databasename];

List all databases on the sql server.

mysql> show databases;

Switch to a database.

mysql> use [db name];

To see all the tables in the db.

mysql> show tables;

To see database’s field formats.

mysql> describe [table name];

To delete a db.

mysql> drop database [database name];

To delete a table.

mysql> drop table [table name];

Show all data in a table.

mysql> SELECT * FROM [table name];

Returns the columns and column information pertaining to the designated table.

mysql> show columns from [table name];

Show certain selected rows with the value “whatever”.

mysql> SELECT * FROM [table name] WHERE [field name] = “whatever”;

Show all records containing the name “Bob” AND the phone number ‘3444444’.

mysql> SELECT * FROM [table name] WHERE name = “Bob” AND phone_number = ‘3444444’;

Show all records not containing the name “Bob” AND the phone number ‘3444444’ order by the phone_number field.

mysql> SELECT * FROM [table name] WHERE name != “Bob” AND phone_number = ‘3444444’ order by phone_number;

Show all records starting with the letters ‘bob’ AND the phone number ‘3444444’.

mysql> SELECT * FROM [table name] WHERE name like “Bob%” AND phone_number = ‘3444444’;

Show all records starting with the letters ‘bob’ AND the phone number ‘3444444’ limit to records 1 through 5.

mysql> SELECT * FROM [table name] WHERE name like “Bob%” AND phone_number = ‘3444444’ limit 1,5;

Use a regular expression to find records. Use “REGEXP BINARY” to force case-sensitivity. This finds any record beginning with a.

mysql> SELECT * FROM [table name] WHERE rec RLIKE “^a”;

Show unique records.

mysql> SELECT DISTINCT [column name] FROM [table name];

Show selected records sorted in an ascending (asc) or descending (desc).

mysql> SELECT [col1],[col2] FROM [table name] ORDER BY [col2] DESC;

Return number of rows.

mysql> SELECT COUNT(*) FROM [table name];

Sum column.

mysql> SELECT SUM(*) FROM [table name];

Join tables on common columns.

mysql> select lookup.illustrationid, lookup.personid,person.birthday from lookup left join person on
lookup.personid=person.personid=statement to join birthday in person table with primary illustration id;

Creating a new user. Login as root. Switch to the MySQL db. Make the user. Update privs.

# mysql -u root -p

mysql> use mysql;

mysql> INSERT INTO user (Host,User,Password) VALUES(‘%’,’username’,PASSWORD(‘password’));

mysql> flush privileges;

Change a users password from unix shell.

# [mysql dir]/bin/mysqladmin -u username -h hostname.blah.org -p password ‘new-password’

Change a users password from MySQL prompt. Login as root. Set the password. Update privs.

# mysql -u root -p

mysql> SET PASSWORD FOR ‘user’@’hostname’ = PASSWORD(‘passwordhere’);

mysql> flush privileges;

Recover a MySQL root password. Stop the MySQL server process. Start again with no grant tables.
Login to MySQL as root. Set new password. Exit MySQL and restart MySQL server.

# /etc/init.d/mysql stop

# mysqld_safe –skip-grant-tables &

# mysql -u root

mysql> use mysql;

mysql> update user set password=PASSWORD(“newrootpassword”) where User=’root';

mysql> flush privileges;

mysql> quit

# /etc/init.d/mysql stop

# /etc/init.d/mysql start

Set a root password if there is on root password.

# mysqladmin -u root password newpassword

Update a root password.

# mysqladmin -u root -p oldpassword newpassword

Allow the user “bob” to connect to the server from localhost using the password “passwd”.
Login as root. Switch to the MySQL db. Give privs. Update privs.

# mysql -u root -p

mysql> use mysql;

mysql> grant usage on *.* to bob@localhost identified by ‘passwd';

mysql> flush privileges;

Give user privilages for a db. Login as root. Switch to the MySQL db. Grant privs. Update privs.

# mysql -u root -p

mysql> use mysql;

mysql> INSERT INTO db (Host,Db,User,Select_priv,Insert_priv,Update_priv,Delete_priv,Create_priv,Drop_priv) VALUES
(‘%’,’databasename’,’username’,’Y’,’Y’,’Y’,’Y’,’Y’,’N’);

mysql> flush privileges;

or

mysql> grant all privileges on databasename.* to username@localhost;

mysql> flush privileges;

To update info already in a table.

mysql> UPDATE [table name] SET Select_priv = ‘Y’,Insert_priv = ‘Y’,Update_priv = ‘Y’ where [field name] = ‘user';

Delete a row(s) from a table.

mysql> DELETE from [table name] where [field name] = ‘whatever';

Update database permissions/privilages.

mysql> flush privileges;

Delete a column.

mysql> alter table [table name] drop column [column name];

Add a new column to db.

mysql> alter table [table name] add column [new column name] varchar (20);

Change column name.

mysql> alter table [table name] change [old column name] [new column name] varchar (50);

Make a unique column so you get no dupes.

mysql> alter table [table name] add unique ([column name]);

Make a column bigger.

mysql> alter table [table name] modify [column name] VARCHAR(3);

Delete unique from table.

mysql> alter table [table name] drop index [colmn name];

Load a CSV file into a table.

mysql> LOAD DATA INFILE ‘/tmp/filename.csv’ replace INTO TABLE [table name] FIELDS TERMINATED BY ‘,’ LINES TERMINATED BY ‘\n’ (field1,field2,field3);

Dump all databases for backup. Backup file is sql mysql-textboxs to recreate all db’s.

# [mysql dir]/bin/mysqldump -u root -ppassword –opt >/tmp/alldatabases.sql

Dump one database for backup.

# [mysql dir]/bin/mysqldump -u username -ppassword –databases databasename >/tmp/databasename.sql

Dump a table from a database.

# [mysql dir]/bin/mysqldump -c -u username -ppassword databasename tablename > /tmp/databasename.tablename.sql

Restore database (or database table) from backup.

# [mysql dir]/bin/mysql -u username -ppassword databasename < /tmp/databasename.sql

Create Table Example 1.

mysql> CREATE TABLE [table name] (firstname VARCHAR(20), middleinitial VARCHAR(3), lastname VARCHAR(35),suffix VARCHAR(3),officeid VARCHAR(10),userid
VARCHAR(15),username VARCHAR(8),email VARCHAR(35),phone VARCHAR(25), groups VARCHAR(15),datestamp DATE,timestamp time,pgpemail VARCHAR(255));

Create Table Example 2.

mysql> create table [table name] (personid int(50) not null auto_increment primary key,firstname varchar(35),middlename varchar(50),lastnamevarchar(50) default
‘bato’);

MYSQL Statements and clauses String Functions Date and Time Functions
ALTER DATABASE

ALTER TABLE

ALTER VIEW

ANALYZE TABLE

BACKUP TABLE

CACHE INDEX

CHANGE MASTER TO

CHECK TABLE

CHECKSUM TABLE

COMMIT

CREATE DATABASE

CREATE INDEX

CREATE TABLE

CREATE VIEW

DELETE

DESCRIBE

DO

DROP DATABASE

DROP INDEX

DROP TABLE

DROP USER

DROP VIEW

EXPLAIN

FLUSH

GRANT

HANDLER

INSERT

JOIN

KILL

LOAD DATA FROM MASTER

LOAD DATA INFILE

LOAD INDEX INTO CACHE

LOAD TABLE…FROM MASTER

LOCK TABLES

OPTIMIZE TABLE

PURGE MASTER LOGS

RENAME TABLE

REPAIR TABLE

REPLACE

RESET

RESET MASTER

RESET SLAVE

RESTORE TABLE

REVOKE

ROLLBACK

ROLLBACK TO SAVEPOINT

SAVEPOINT

SELECT

SET

SET PASSWORD

SET SQL_LOG_BIN

SET TRANSACTION

SHOW BINLOG EVENTS

SHOW CHARACTER SET

SHOW COLLATION

SHOW COLUMNS

SHOW CREATE DATABASE

SHOW CREATE TABLE

SHOW CREATE VIEW

SHOW DATABASES

SHOW ENGINES

SHOW ERRORS

SHOW GRANTS

SHOW INDEX

SHOW INNODB STATUS

SHOW LOGS

SHOW MASTER LOGS

SHOW MASTER STATUS

SHOW PRIVILEGES

SHOW PROCESSLIST

SHOW SLAVE HOSTS

SHOW SLAVE STATUS

SHOW STATUS

SHOW TABLE STATUS

SHOW TABLES

SHOW VARIABLES

SHOW WARNINGS

START SLAVE

START TRANSACTION

STOP SLAVE

TRUNCATE TABLE

UNION

UNLOCK TABLES

USE

AES_DECRYPT

AES_ENCRYPT

ASCII

BIN

BINARY

BIT_LENGTH

CHAR

CHAR_LENGTH

CHARACTER_LENGTH

COMPRESS

CONCAT

CONCAT_WS

CONV

DECODE

DES_DECRYPT

DES_ENCRYPT

ELT

ENCODE

ENCRYPT

EXPORT_SET

FIELD

FIND_IN_SET

HEX

INET_ATON

INET_NTOA

INSERT

INSTR

LCASE

LEFT

LENGTH

LOAD_FILE

LOCATE

LOWER

LPAD

LTRIM

MAKE_SET

MATCH AGAINST

MD5

MID

OCT

OCTET_LENGTH

OLD_PASSWORD

ORD

PASSWORD

POSITION

QUOTE

REPEAT

REPLACE

REVERSE

RIGHT

RPAD

RTRIM

SHA

SHA1

SOUNDEX

SPACE

STRCMP

SUBSTRING

SUBSTRING_INDEX

TRIM

UCASE

UNCOMPRESS

UNCOMPRESSED_LENGTH

UNHEX

UPPER

ADDDATE

ADDTIME

CONVERT_TZ

CURDATE

CURRENT_DATE

CURRENT_TIME

CURRENT_TIMESTAMP

CURTIME

DATE

DATE_ADD

DATE_FORMAT

DATE_SUB

DATEDIFF

DAY

DAYNAME

DAYOFMONTH

DAYOFWEEK

DAYOFYEAR

EXTRACT

FROM_DAYS

FROM_UNIXTIME

GET_FORMAT

HOUR

LAST_DAY

LOCALTIME

LOCALTIMESTAMP

MAKEDATE

MAKETIME

MICROSECOND

MINUTE

MONTH

MONTHNAME

NOW

PERIOD_ADD

PERIOD_DIFF

QUARTER

SEC_TO_TIME

SECOND

STR_TO_DATE

SUBDATE

SUBTIME

SYSDATE

TIME

TIMEDIFF

TIMESTAMP

TIMESTAMPDIFF

TIMESTAMPADD

TIME_FORMAT

TIME_TO_SEC

TO_DAYS

UNIX_TIMESTAMP

UTC_DATE

UTC_TIME

UTC_TIMESTAMP

WEEK

WEEKDAY

WEEKOFYEAR

YEAR

YEARWEEK

Mathematical and Aggregate Functions Flow Control Functions/Command-Line Utilities PHP API – using functions built into PHP with MySQL
ABS

ACOS

ASIN

ATAN

ATAN2

AVG

BIT_AND

BIT_OR

BIT_XOR

CEIL

CEILING

COS

COT

COUNT

CRC32

DEGREES

EXP

FLOOR

FORMAT

GREATEST

GROUP_CONCAT

LEAST

LN

LOG

LOG2

LOG10

MAX

MIN

MOD

PI

POW

POWER

RADIANS

RAND

ROUND

SIGN

SIN

SQRT

STD

STDDEV

SUM

TAN

TRUNCATE

VARIANCE

CASE

IF

IFNULL

NULLIF

Command-Line Utilities

comp_err

isamchk

make_binary_distribution

msql2mysql

my_print_defaults

myisamchk

myisamlog

myisampack

mysqlaccess

mysqladmin

mysqlbinlog

mysqlbug

mysqlcheck

mysqldump

mysqldumpslow

mysqlhotcopy

mysqlimport

mysqlshow

perror

mysql_affected_rows

mysql_change_user

mysql_client_encoding

mysql_close

mysql_connect

mysql_create_db

mysql_data_seek

mysql_db_name

mysql_db_query

mysql_drop_db

mysql_errno

mysql_error

mysql_escape_string

mysql_fetch_array

mysql_fetch_assoc

mysql_fetch_field

mysql_fetch_lengths

mysql_fetch_object

mysql_fetch_row

mysql_field_flags

mysql_field_len

mysql_field_name

mysql_field_seek

mysql_field_table

mysql_field_type

mysql_free_result

mysql_get_client_info

mysql_get_host_info

mysql_get_proto_info

mysql_get_server_info

mysql_info

mysql_insert_id

mysql_list_dbs

mysql_list_fields

mysql_list_processes

mysql_list_tables

mysql_num_fields

mysql_num_rows

mysql_pconnect

mysql_ping

mysql_query

mysql_real_escape_string

mysql_result

mysql_select_db

mysql_stat

mysql_tablename

mysql_thread_id

mysql_unbuffered_query

Share
Categories : MySQL Tags :

What is New In MySQL 5.0?

Posted by 16 September, 2010 (0) Comment

MySQL is mostly used for web development in the Linux environment. Specially LAMP. It is the “M” in the acronym LAMP (Linux operating system, Apache web server, MySQL database, and Perl / PHP / Python scripting languages).
MySQL is usually described as open source. MySQL is actually available under both free and commercial licenses. MySQL is licensed under the GNU Public License (GPL).

Stored program objects are the most valuable significant upgrade to MySQL5.0.
A) Views
B)  Stored Procedures
C)  Functions
D)  Triggers

Views

A view is a virtual table:  a SELECT statement with a name. Microsoft SQL Server calls them views as well; Microsoft Access calls them queries. Selecting from the view name executes the underlying SELECT statement, and returns the results as columns in the virtual table. MySQL views may be read only or updateable. A check option can be specified to prevent views from being updated with rows that they cannot themselves SELECT

Disadvantage.

It is not possible to create an index on a view.

Subqueries cannot be used in the FROM clause of a view.

There is a general principle that you cannot modify a table and select from the same table in a subquery.

Example

CREATE VIEW view_name AS
SELECT column_name(s)
FROM table_name
WHERE condition

Stored procedures

Stored procedures are created via the CREATE PROCEDURE statement, and executed via the CALL statement. They may include input, output, and input-output parameters. MySQL stored procedures follow the SQL Server model, which permits a rowset to be returned simply by including a SELECT statement in the procedure. Unlike SQL Server, however, stored procedures in MySQL are not compiled. They do share many of the same advantages, such as standardizing code and reducing network traffic by performing business logic within the server.

Why use Stored Procedures?

Stored procedures are fast!  It takes some advantage of caching, just as prepared statements do. There is no compilation, so an SQL stored procedure won’t work as quickly as a procedure written with an external language such as C.
2.  Stored procedures are components! Suppose that you change your host language — no problem, the logic is in the database not the application.
3.  Stored procedures are portable! When you write your stored procedure in SQL, you know that it will run on every platform that MySQL runs on, without obliging you to install an additional runtime-environment package.
4. Stored procedures are stored! If you write a procedure with the right naming conventions, for example saying chequing_withdrawal for a bank transaction, then people who want to know about chequing can find your procedure. It’s always available as ‘source code’ in the database itself.
5. Stored procedures are migratory! MySQL adheres fairly closely to the SQL:2003 standard. Others (DB2, Mimer) also adhere. Others (Oracle, SQL Server).

A stored procedure has a name, a parameter list, and an SQL statement, which can contain many more SQL statements. There is new syntax for local variables, error handling, loop control, and IF conditions. Here is an example of a statement that creates a stored procedure.

CREATE PROCEDURE procedure1                /* name */
(IN parameter1 INTEGER)                    /* parameters */
BEGIN                                      /* start of block */
  DECLARE variable1 CHAR(10);                /* variables */
  IF parameter1 = 17 THEN                    /* start of IF */
    SET variable1 = 'birds';                   /* assignment */
  ELSE
    SET variable1 = 'beasts';                  /* assignment */
  END IF;                                   /* end of IF */
  INSERT INTO table1 VALUES (variable1);    /* statement */
END                                       /* end of block */

What I’m going to do is explain in detail all the things you can do with stored procedures. We’ll also get into another new database object, triggers, because there is a tendency to associate triggers with stored procedures.

Triggers

Triggers are event-driven stored procedures. They are tied to a specific table, and to an event on that table (INSERT, UPDATE, or DELETE). When the event occurs, the trigger is executed (or “fired”.)
One key difference between MySQL triggers and those in SQL Server is that MySQL triggers can be called either before the triggering action or after it, whereas SQL Server triggers are after only. SQL Server does have an INSTEAD OF trigger not present in MySQL. Another key difference is the FOR EACH ROW syntax in MySQL, that will cause the trigger to execute for each row modified. The prefixes “OLD.” and “NEW.” enable the trigger body to reference columns before or after being modified. SQL Server triggers execute once per statement, and must take into account the possibility of multiple rows being affected.

Storage enhancements and tools

1.  VARCHAR can store max of 65,532 bytes
2.  There is a new BIT datatype.
3.  MySQL’s architecture uses plug-in storage engines to implement the physical storage of database tables.
4.  Each table may use a different storage engine.
5.  The default storage engine, MyISAM, is very fast but does not have the ability to capture transactions.
6.  InnoDB storage engine is good for transactions, and aslo provide row-level locking.
7.  The InnoDB engine uses a more compact storage format than previously.
8.  MySql 5.0 have new storage engine types to the product: Archive, and Federated
9.  The Federated storage engine enables access to remote tables, similar to a linked server definition in Microsoft SQL Server.
10.  MySql now includes a set of graphical user interfaces for common administration and development tasks.

  • MySQL Instance Configuration Wizard – This tool is a step-by-step guide to configuring an instance of MySQL. Specifically, it creates the my.ini file, a text file containing startup configuration parameters.
  • MySQL Query Browser – This tool can be used to build queries and test them. It’s similar to Query Analyzer in SQL Server 7.0 and     2000, with a schemata browser
  • MySQL Administrator – Common administrative tasks such as creating, altering, and dropping tables in a database can be performed visually via the Table Editor. Indexes and constraints such as foreign keys can also be defined here.
  • MySQL System Tray Monitor - Similar to the Service Manager in SQL Server 2000, this tool puts an icon in the Windows SysTray to display the status of the MySQL Instance.
Share
Categories : MySQL Tags :

How to Stop SQL Injection in MYSQL?

Posted by 9 August, 2009 (4) Comment

Every PHP-MYSQL programmer need to know Anti-SQL Injection.

Please take a look at very simple function which can save your database!!

<?Php
 
function ClearInput($dirty){
 
	if (get_magic_quotes_gpc()) {
 
	$clean = mysql_real_escape_string(stripslashes($dirty));
 
	}else{
 
	$clean = mysql_real_escape_string($dirty);
 
	}
	return $clean;
 
}
 
?>
Share
Categories : Easy PHP,MySQL,PHP Tags :

Commonly Used MySQL Commands.

Posted by 20 January, 2009 (0) Comment

To login from linux shell
Mysql>;  -h hostname -u root -p

List all available databases with that username.
Show databases;

To use a database -
Use dbname;

To see tables within selected database;
show tables;

To see table field formats;
describe [xyzTableName];

To delete database -
Drop database [xyzDatabase];

To delete a table –

Drop table [xyzTableName];

Show all data in a table –
SELECT * FROM  xyzTableName;

Share
Categories : MySQL Tags :