Thursday 19 February 2015
CREATE FOREIGN KEY (FK) DIY FROM ENGINE MYSQL 'MYISAM'
Posted by
Unknown,
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05:46
MyISAM is an abbreviation of " MySQL Indexed Sequential Access Method". MyISAM has some drawbacks compared to InnoDB. Therefore, here I will try to overcome one of the shortcomings that exist in MyISAM is no foreign key in this engine. For more details, refer all right myexplanation below: 1. The first step to be done is to create a database testing, for example with the name testdb. Command: CREATE DATABASE testdb; 2. The second step, namely : create three tables. # Table ERROR_MSG useful to accommodate the error message. # Table Log in handy as the child table. # User table useful as a parent table Command: Table error_msg CREATE TABLE `error_msg` ( `error_msg` VARCHAR(50) NULL DEFAULT NULL ) ENGINE=MyISAM;
Insert error_msg values ('Data sedang digunakan tabel lain');Insert error_msg values ('Data tidak ada dalam parameter');Table login (Table Anak)CREATE TABLE `login`(`username` VARCHAR(50) NOT NULL,`password` VARCHAR(50) NOT NULL,`id_user` INT(11) NOT NULL,PRIMARY KEY (`username`))ENGINE=MyISAM;INSERT INTO `testdb`.`login` (`username`, `password`, `id_user`) VALUES ('SWW', '123', 1);Table user (Table Induk) CREATE TABLE `user` (`id_user` INT(11) NOT NULL AUTO_INCREMENT,`nama` VARCHAR(50) NULL DEFAULT NULL,PRIMARY KEY (`id_user`))COLLATE='latin1_swedish_ci'ENGINE=MyISAMAUTO_INCREMENT=2;INSERT INTO `testdb`.`user` (`id_user`, `nama`) VALUES (1, 'HUSNIAH');INSERT INTO `testdb`.`user` (`id_user`, `nama`) VALUES (2, 'RANUAH');2. The third step , namely : make 4 pieces trigger . Trigger delete parent tableCREATE TRIGGER `delete_induk` BEFORE DELETE ON `user` FOR EACH ROW BEGIN IF(SELECT COUNT(*) FROM login WHERE login.id_user = old.id_user)>0 THEN insert error_msg VALUES('Data sedang digunakan tabel lain'); END IF; END
Thursday 12 February 2015
Computer Definition According to Experts
Posted by
Unknown,
on
10:29
Donald H. Sanderes
The computer is an electronic system that has the ability to manipulate data quickly and accurately as well as designed and organized to automatically receive and store input data, processes it, and produces output under the supervision of a step by step instruction program (Operating System) which is stored in the inside stored program.
Robert H. Blissmer
Computer is an electronic device which has the ability to do some telecoms like accept input, input processing, storing commands, and provide output.
Hamacher
The Computer is an electronic calculating machine that quickly and can receive digital input information then process it in accordance with a program stored in memory and generate output information.
Wikipedia
The computer is a tool used to process data base on procedures defined. The word was originally used computer to describe a person whose job it perform arithmetic calculations, with or without tools, but the meaning of the initials then moved addressed to the machine itself. Originally, Information Processing almost exclusively related to arithmetical problems, but modern computers are used for many telecoms are not related to mathematics.
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