CSCI 6962: Server-side Design and Programming Server-side Databases and Drivers 1

Outline Database servers and drivers Databases and the MVC paradigm SQL overview The Derby database server Creating databases Populating a database MySQL

Databases and E-Commerce Long term information stored in databases Queries used to produce lists of products Updates used to store orders New record created for order in Order table Customer information added to other tables Quantities updated in inventory tables

Database Access Object Database Servers Access to database controlled by database server Constantly running (like web container) Server runs database queries and updates for databases it controls Server handles security of database Most are password-controlled MySQL (free) Oracle MS Server Not Access! Database server Web server database Database Access Object

Database Servers Programs create statement objects inside server Server executes them on the database Server stores results if query performed Program may then access those results Database server Web server Statement object select * from books database Database Access Object ResultSet object productCode title price productCode title price productCode title price

Database Drivers Database server does not understand Java/C# commands Only understands its own DBMS protocols Each server has its own DBMS Need a database driver to perform translation Obtain from database server provider Install in Java libraries web container database server JDBC database driver JSF page Managed bean/ support class DBMS

Databases and the MVC Paradigm Usually do not directly access database from JSF/ASP pages Requires both web programming and SQL knowledge Usually done in model classes (such as managed bean) Bean stores to database when commanded to Bean performs database query when need to retrieve data Often have built-in tools for database management SqlDataSource object in ASP web container database server JSF pages/ Managed bean Support classes/ tools ASP pages/ Code behind

SQL and Databases Commands to database server use SQL (structured query language) Common examples: Query for all records matching some condition: select field from table where condition Example: select * from books where price < 10 Delete all records matching some condition: delete from table where condition Example: delete from books where ISBN = ‘0004’

SQL and Databases Set new field value for all records matching some condition: update table set field = value WHERE condition Example: update books set price = 9.95 where productCode = ‘0004’ Insert new record with given field values: insert into table (field, field, field…) values (value, value, value…) Example: insert into books (productCode, title, price) values (‘0004’, ‘Green Eggs and Ham’, 9.95)

Derby Open source database server from Apache Not as powerful as MySql, Oracle, etc. Low memory overhead Fewer access privileges required Included in later versions of NetBeans Create database, create connection to it Create tables and execute SQL commands Manipulate database from Java program running in NetBeans

Creating a Derby Database Go to Services tab Expand Databases node Right-click Java DB node Choose Create Database

Creating a Derby Database Give database a name Set User name to app Strange schema errors otherwise Set a password (I usually also just use “app”)

Creating a Derby Database Must connect to the database before using Right-click on link corresponding to database Choose Connect

Adding a Table Expand link to database Expand App node Right-click Tables node Select Create Table Will get Create Table dialog

Adding a Table Add column for each field of table First field should be key field Check Primary key Check Unique Set types and other properties as needed # of characters in VARCHAR Etc.

Adding a Table Final table structure now shown in services window

Manipulating the Database Can execute queries directly (without using code) Right click table Select Execute Command Brings up command window Type in SQL statement Right-click window Select Run Statement

Viewing the Database Right click table Select View Data Executes SELECT * FROM tablename query

MySQL Free database server Go to www.mysql.com Follow Products tab Go to MySQL Community Server Download and run

MySQL Database Driver From downloads page at mysql.com Go to connectors page Go to Connector/J (for Java) Download and save Extract the mysql-connector-java-5.version-bin.jar file

MySQL Database Driver In Netbeans right-click Libraries folder of project Choose Add JAR/Folder Select mysql-connector-java-5. version-bin.jar file from downloads

The MySQL Interface Command line interface to manipulate databases MySQL controls Available from PROGRAMS menu Will need to give password Can create new databases create database databasename;

Creating Database Tables Must define field names and field types Some types: varChar(n) : String of up to n characters int(n) : integer up to n digits double(n, d) : decimal number up to n digits and d after the decimal Must declare a key field with “primary key” create table tablename ( keyfieldname type primary key, fieldname type, fieldname type, … );