Paul Jacobs The iSchool University of Maryland Thursday, Oct. 5, 2017 INFM 603: Session 6 Database Implementation Using PHP and MySQL Paul Jacobs The iSchool University of Maryland Thursday, Oct. 5, 2017 This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States See http://creativecommons.org/licenses/by-nc-sa/3.0/us/ for details

Today’s Topics Review of Database Fundamentals How to Build/Query/Update Online Relational Databases Hands-on Practice

Database Fundamentals - Review What is a database? A computer mechanism for online persistent storage, organization and access to information (a technology) Why do we need them? To maintain information in a consistent, convenient, reliable way that enables applications (a tier or architectural component) How do we use them? Building a (usually) relational model called a schema that organizes data in tables and supports needed functionality; writing code for interfaces (implementation) Database Fundamentals Implementation Hands-on Practice

Database Implementation – Types of Database Problems Design and Document a Database Figure out what data has to be in there How is the data structured? What are the types of data (e.g., names, dates, strings, etc.)? Build the schema Document it (so that you or someone else can implement it) Build a Database Create the database (tables), users, security, etc. (usually done by designer and/or DBA – administrator using various interfaces and/or ODBC/SQL) Validate that it works Populate the database (enter records) Database Fundamentals Implementation Hands-on Practice

Database Implementation –Database Problems (cont’d) Program a Database Develop interfaces for end users (e.g. to search, access information from databases – e.g., Testudo) Develop interfaces for other systems (e.g., to place orders, perform updates, etc. – e.g., Canvas, Amazon) Query a Database Access data (records) already in the database Can be done using all kinds of interfaces, or by programs (often using ODBC/SQL) Very often done by users who are not allowed to update or change the data themselves Database Fundamentals Implementation Hands-on Practice

Documenting a Database Usually specifies the schema, especially the tables (or object classes in an object-oriented format), but can be at various levels and description and abstraction Can be used to communicate among different parts of a technical project team (e.g., user groups, programmers, database designers, etc.) Can use any number of documentation methods E-R diagrams Class diagrams with annotations Sketches and drawings of all sorts (such as what we used last time) Actual database output from some stage of implementation Best done relatively early in project because of need to build and test code to interface with the database Database Fundamentals Implementation Hands-on Practice

Database Implementation - Introduction to SQL

What is SQL (Structured Query Language)? The “interlingua” of relational databases (e.g., Oracle, SQLServer, MySQL, Postgres, DB2, etc.) An international standard (ISO 9075) A common method of building and querying databases A common method of building database interfaces (e.g., using ASP, JSP, PHP) A common method of building connectors from applications to databases (e.g., using XML, SOAP and ODBC/JDBC) Database Fundamentals Implementation Hands-on Practice

Basic SQL functions (on records) SELECT – get records from a database that meet certain criteria INSERT – add records to a database UPDATE DELETE Database Fundamentals Implementation Hands-on Practice

Basic SQL functions - SELECT SELECT CustomerAddress FROM Customers WHERE CustomerName = ‘Will E. Coyote’; SELECT * FROM SalesOrders LIMIT 0,30; Database Fundamentals Implementation Hands-on Practice

PHPMyAdmin Output - SELECT Database Fundamentals Implementation Hands-on Practice

SELECT Using JOIN SELECT SalesOrders.SalesOrderNo, Customers.CustomerName FROM SalesOrders JOIN Customers ON (SalesOrders.CustomerNo = Customers.CustomerNo) ; Database Fundamentals Implementation Hands-on Practice

PHPMyAdmin Output - Join Database Fundamentals Implementation Hands-on Practice

Basic SQL functions - INSERT INSERT INTO `inclassdemo`.`OrderItems` ( `SalesOrderNo` , `ItemNo` , `ItemQuantity` , `ItemUnitPrice` ) VALUES ( '1', '1', '12', '10.50'); Database Fundamentals Implementation Hands-on Practice

Basic SQL functions - UPDATE UPDATE `inclassdemo`.`SalesOrders` SET `CustomerNo` = '5', `ClerkNo` = '2' WHERE `SalesOrders`.`SalesOrderNo` =1 LIMIT 1 ; Database Fundamentals Implementation Hands-on Practice

Basic SQL functions - DELETE DELETE FROM Customers WHERE CustomerName = 'Peter Piper'; Database Fundamentals Implementation Hands-on Practice

Basic SQL functions (on tables) CREATE – make a new table DROP – delete a table ALTER – change (e.g., fields) of a table Database Fundamentals Implementation Hands-on Practice

Basic SQL functions - CREATE CREATE TABLE `SalesOrders` ( `SalesOrderNo` INT( 6 ) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY , `Date` DATE NOT NULL , `CustomerNo` INT NOT NULL , `ClerkNo` INT NOT NULL , `Total` FLOAT( 9, 2 ) NOT NULL ) [in MySQL requires separate constraint PRIMARY KEY (SalesOrderNo)] Database Fundamentals Implementation Hands-on Practice

Basic SQL functions – DROP AND ALTER DROP TABLE Pets; ALTER TABLE SalesOrders ADD Season VARCHAR (10); Database Fundamentals Implementation Hands-on Practice

Building the Sample Database Using MySQL

Example Database (Final Tables) Table: SalesOrders SalesOrderNo Date CustomerNo ClerkNo Total Table: OrderItems ItemNo ItemQuantity ItemUnitPrice Table: InventoryItems ItemNo ItemDescription Table: Customers CustomerNo CustomerName CustomerAddress Table: Clerks ClerkNo ClerkName Database Fundamentals Implementation Hands-on Practice

Building the Sample With PHPMyadmin – Create Tables Database Fundamentals Implementation Hands-on Practice

Building the Sample With PHPMyadmin – Add Data Database Fundamentals Implementation Hands-on Practice

Building the Sample With PHPMyadmin – Add Data (SQL) Database Fundamentals Implementation Hands-on Practice

Building the Sample With PHPMyadmin – Build Queries Database Fundamentals Implementation Hands-on Practice

Build and populate the sample database Hands On Practice Build and populate the sample database

SQL is Quite Powerful Data types – Most common are INT (Integer), VARCHAR (Variable length string), and DATE, but there are many other related types, e.g. TIMESTAMP, BLOB (binary large object), FLOAT (floating point) Functions – There are functions for almost any data type, e.g. – Date conversion and formatting, such as DATE_FORMAT(Date, ‘%b . %m, %Y) TIMESTAMPDIFF(YEAR, BirthDate,CURDATE()) All kinds of arithmetic, like SQRT() and POW() Numerous tools and tricks for manipulating, sorting, comparing, etc. Database Fundamentals Implementation Hands-on Practice

Example: Typical Contact DB Database Fundamentals Implementation Hands-on Practice

Example: Age Query Database Fundamentals Implementation Hands-on Practice

Example: Birthday Query Database Fundamentals Implementation Hands-on Practice

Database Implementation - Recap Reviewed the role of databases in [web] applications Introduced SQL as the “interlingua” of relational databases Presented and tried out one type of database server using PHPMyAdmin/MySQL Next up: Integrating with web pages via PHP and other advanced methods, tying things together Database Fundamentals Implementation Hands-on Practice