Difference between revisions of "CSC220 Lab 5 MySQL"

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(Delete Table)
(Insert Data in Tables)
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  INSERT INTO `users`(`userId`,`userName`) VALUES ( NULL,'Marie');
 
  INSERT INTO `users`(`userId`,`userName`) VALUES ( NULL,'Marie');
 +
 +
* Verify that the information ends up in the table, as expected.
  
 
==Inserting into Items==
 
==Inserting into Items==
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  INSERT INTO `orders`(`orderId`,`userId`,`itemId`) VALUES ( NULL,'1','2');
 
  INSERT INTO `orders`(`orderId`,`userId`,`itemId`) VALUES ( NULL,'1','2');
 +
 +
 +
=Modifying information already in the database=
 +
 +
* The query below modifies the Item whose Id is 2 and changes its '''itemName''' to ''eraser'' and its '''price''' to ''0.5''.
 +
 +
UPDATE `items` SET  `itemName`='eraser',`price`='0.5' '''WHERE''' `itemId`='2';
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 +
* Modify a few entries in your 3 different tables, just to get familiar with the '''UPDATE''' command.

Revision as of 12:29, 12 October 2010

Creating the Databases and the Users

  • This section is just for completeness and does not have to be performed. Only the admin of the database can create databases. Just read this section and start working on the next one.
  • for all accounts from aa to ao, run the query
CREATE DATABASE `220a-ac`CHARACTER SET utf8 COLLATE utf8_general_ci;
  • Similarly, create users with same name
 INSERT INTO mysql.user ( HOST, USER, PASSWORD, select_priv, insert_priv,
      update_priv, delete_priv,  create_priv, drop_priv, reload_priv, shutdown_priv, 
      process_priv,  file_priv, grant_priv, references_priv, index_priv, alter_priv, 
      show_db_priv, super_priv, create_tmp_table_priv, lock_tables_priv, 
      execute_priv, repl_slave_priv, repl_client_priv, create_view_priv, show_view_priv,
      create_routine_priv, alter_routine_priv, create_user_priv )
      VALUES ( 'localhost', '220a-ac', PASSWORD('AStrangeWordUsedForPassword'), 
      'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N',
      'N', 'N', 'N', 'N', 'N', 'N', 'N', 'N' );
  • Then make that user get all privileges on the database with the same name
  DELETE FROM mysql.db WHERE USER='220a-ac' AND HOST='localhost';
  DELETE FROM mysql.tables_priv WHERE USER='220a-ac' AND HOST='localhost';
  DELETE FROM mysql.columns_priv WHERE USER='220a-ac' AND HOST='localhost';
  DELETE FROM mysql.procs_priv WHERE USER='220a-ac' AND HOST='localhost';
  INSERT INTO mysql.db(HOST, db, USER, Select_priv, Insert_priv, Update_priv, "
          Delete_priv, Create_priv, Drop_priv, Grant_priv, References_priv, Index_priv,"
          Alter_priv, create_tmp_table_priv, lock_tables_priv, Create_view_priv, Show_view_priv,"
          Create_routine_priv, Alter_routine_priv, Execute_priv) "
         VALUES( 'localhost', '220a-ac', '220a-ac', 'Y','Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y',"
          'Y', 'Y', 'Y', 'Y' );

Login to the Database


This section is only visible to computers located at Smith College

Create Tables

  • You are going to create 3 tables: users, orders, and items
    • users contains an Id and a name field.
    • orders contains an Id for the order, an Id for the user ordering, and an item ordered
    • items contains and Id, a name, and a price

Create the Tables

Users

  • Click on the SQL tab
  • enter the following query in the text area:
CREATE TABLE `users` (
`userId` INT(1) NOT NULL AUTO_INCREMENT,
`userName` VARCHAR(100) DEFAULT NULL,
PRIMARY KEY  (`userId`)
) ENGINE=MYISAM DEFAULT CHARSET=utf8;
  • Click the Go button
  • You should see a new table appear in the left, blueish, column. Click on it.
  • Click on the Browse and Structure tabs to see two different views of the table.

Orders

  • similarly, create the Orders table:
CREATE TABLE `orders` (
`orderId` INT(1) NOT NULL AUTO_INCREMENT,
`userId` INT(1) DEFAULT NULL,
`itemId` INT(1) DEFAULT NULL,
PRIMARY KEY  (`orderId`)
) ENGINE=MYISAM DEFAULT CHARSET=utf8;


Items

  • And finally create the Items table:
CREATE TABLE `items` (
`itemId` INT(1) NOT NULL AUTO_INCREMENT,
`itemName` VARCHAR(100) DEFAULT NULL,
`price` FLOAT DEFAULT NULL,
PRIMARY KEY  (`itemId`)
) ENGINE=MYISAM DEFAULT CHARSET=utf8;

Summary

  • You should have 3 tables in your database:
PHPMyAdminLab5b.png

Delete Table

  • Just to see how this is done, you are going to delete (drop) one of the tables from your database, and recreate it.
  • Make phpMyAdmin show you the same page as shown in the image above.
  • Select the table you want to delete
  • In the With Selected, pick drop
  • then click on Go
  • confirm.
  • The table should be gone.
  • You may want to recreate the table with a new CREATE TABLE query.

Insert Data in Tables

  • The trick is to type the INSERT query once in the SQL box, and change just the value, and submit the query many times.


Inserting into Users

  • Create several users with the following query:
INSERT INTO `users`(`userId`,`userName`) VALUES ( NULL,'Marie');
  • Verify that the information ends up in the table, as expected.

Inserting into Items

  • Create several items with the following query:
INSERT INTO `items`(`itemId`,`itemName`,`price`) VALUES ( NULL,'pencil','1');

Inserting into Orders

  • Similarly for the table Orders. The query below indicates that the user whose Id is 1 ordered an item whose Id is 2
INSERT INTO `orders`(`orderId`,`userId`,`itemId`) VALUES ( NULL,'1','2');


Modifying information already in the database

  • The query below modifies the Item whose Id is 2 and changes its itemName to eraser and its price to 0.5.
UPDATE `items` SET  `itemName`='eraser',`price`='0.5' WHERE `itemId`='2';
  • Modify a few entries in your 3 different tables, just to get familiar with the UPDATE command.