Database Systems. S. Adams. Dilbert. Available: Hans-Petter Halvorsen

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1 Database Systems S. Adams. Dilbert. Available: Hans-Petter Halvorsen

2 Old fashion Database (Data-storage) Systems Not too long ago, this was the only data-storage device most companies needed. Those days are over.

3 Testing Implementation Deployment Maintenance The Software Development Lifecycle Planning Requirements Analysis Design

4 Database Systems A Database is a structured way to store lots of information. The information is stored in different tables. - Everything today is stored in databases! Examples: Bank/Account systems Information in Web pages such as Facebook, Wikipedia, YouTube, etc. Fronter, TimeEdit, etc. lots of other examples!

5 Example: Database ER Diagram 5

6 Database Management Systems (DBMS) Microsoft SQL Server Enterprise, Developer versions, etc. (Professional use) Express version is free of charge Oracle MySQL (owned by Oracle, but previously owned by Sun Microsystems) - MySQL can be used free of charge (open source license), Web sites that use MySQL: YouTube, Wikipedia, Facebook Microsoft Access IBM DB2 Sybase MariaDB MongoDB etc.

7 Database Types Relation Database/SQL Databases Microsft SQL Server Oracle MySQL MariaDB etc. NoSQL Databases MongoDB etc.

8 SQL vs. NoSQL Database Types 8

9 Database Modelling Hans-Petter Halvorsen, M.Sc.

10 Database Modelling The logical structure of the database ER Diagram (Entity Relationship)

11 Database Design ER Diagram ER Diagram (Entity-Relationship Diagram) Used for Design and Modeling of Databases. Specify Tables and relationship between them (Primary Keys and Foreign Keys) Example: Table Name Table Name Primary Key Primary Key Foreign Key Column Names Relational Database. In a relational database all the tables have one or more relation with each other using Primary Keys (PK) and Foreign Keys (FK). Note! You can only have one PK in a table, but you may have several FK s.

12 Database Design Tools Visio PowerDesigner CA ERwin CA ERwin Data Modeler Community Edition Community Edition is Free, 25 objects limit Support for Oracle, SQL Server, MySQL, ODBC, Sybase Toad Data Modeler A Simple designer is also included with SQL Server (physical model, not logical model)

13 Database - Best Practice Tables: Use upper case and singular form in table names not plural, e.g., STUDENT (not students) Columns: Use Pascal notation, e.g., StudentId Primary Key: If the table name is COURSE, name the Primary Key column CourseId, etc. Always use Integer and Identity(1,1) for Primary Keys. Use UNIQUE constraint for other columns that needs to be unique, e.g. RoomNumber Specify Required Columns (NOT NULL) i.e., which columns that need to have data or not Standardize on few/these Data Types: int, float, varchar(x), datetime, bit Use English for table and column names Avoid abbreviations! (Use RoomNumber not RoomNo, RoomNr,...)

14 Database Design Microsoft Visio We will use Visio to Design our Database 1 2 Select the proper Template 3 14

15 Table Name ER Diagram Example - Visio Primary Key (PK) Foreign Key (FK)

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17 ER Diagram Example using built-in Designer in Microsoft SQL Server Table Name PK Table Name PK FK PK-FK Relationship Table Name PK FK PK FK FK Table Name Table Name PK FK Table Name PK FK PK PK-FK Relationships FK FK Table Name Table Name PK FK FK PK Primary Key, FK Foreign Key 17

18 Hans-Petter Halvorsen, M.Sc.

19 SQL Server Main parts: SQL Server Engine + Management Studio SQL Server Standard, Developer, Web, Enterprise, Datacenter,... Free Alternative: SQL Server Express SQL Azure Database Cloud-based version

20 Microsoft SQL Server SQL Server consists of a Database Engine and a Management Studio. The Database Engine has no graphical interface - it is just a service running in the background of your computer (preferable on the server). The Management Studio is graphical tool for configuring and viewing the information in the database. It can be installed on the server or on the client (or both).

21 Microsoft SQL Server Your SQL Server Your Database 4 Write your Query here Your Tables 5 The result from your Query

22 Microsoft SQL Server Create a New Database 2 1 Name you database, e.g., WEATHER_SYSTEM

23 Microsoft SQL Server Tips and Tricks Do you get an error when trying to change your tables? Make sure to uncheck this option!

24 SQL Structured Query Language Hans-Petter Halvorsen, M.Sc.

25 SQL Structured Query language A Database Computer Language designed for Managing Data in Relational Database Management Systems (RDBMS) Query Examples: insert into STUDENT (Name, Number, SchoolId) values ('John Smith', '100005', 1) select SchoolId, Name from SCHOOL select * from SCHOOL where SchoolId > 100 update STUDENT set Name='John Wayne' where StudentId=2 delete from STUDENT where SchoolId=3 We have 4 different Query Types (CRUD): INSERT, SELECT, UPDATE and DELETE CRUD Create (Insert), Read (Select), Update and Delete

26 Create Tables using the Designer Tools in SQL Server Even if you can do everything using the SQL language, it is sometimes easier to do something in the designer tools in the Management Studio in SQL Server. Instead of creating a script you may as well easily use the designer for creating tables, constraints, inserting data, etc. 1 2 Select New Table : Next, the table designer pops up where you can add columns, data types, etc. In this designer we may also specify constraints, such as primary keys, unique, foreign keys, etc.

27 Create Tables with the Database Diagram 1 2 You may select existing tables or create new Tables Create New Table Enter Columns, select Data Types, Primary Keys, etc.

28 if not exists (select * from dbo.sysobjects where id = object_id(n'[school]') and OBJECTPROPERTY(id, N'IsUserTable') = 1) CREATE TABLE [SCHOOL] ( [SchoolId] [int] IDENTITY(1, 1) NOT NULL PRIMARY KEY, [SchoolName] [varchar](50) NOT NULL UNIQUE, [Description] [varchar](1000) NULL, [Address] [varchar](50) NULL, [Phone] [varchar](50) NULL, [PostCode] [varchar](50) NULL, [PostAddress] [varchar](50) NULL, ) GO Create Tables using SQL if not exists (select * from dbo.sysobjects where id = object_id(n'[class]') and OBJECTPROPERTY(id, N'IsUserTable') = 1) CREATE TABLE [CLASS] ( [ClassId] [int] IDENTITY(1, 1) NOT NULL PRIMARY KEY, [SchoolId] [int] NOT NULL FOREIGN KEY REFERENCES [SCHOOL] ([SchoolId]), [ClassName] [varchar](50) NOT NULL, [Description] [varchar](1000) NULL, ) GO

29 Get Data from multiple tables in a single Example: Query using Joins select SchoolName, CourseName from You link Primary Keys and Foreign Keys together SCHOOL inner join COURSE on SCHOOL.SchoolId = COURSE.SchoolId

30 Creating Views using the Editor 3 1 Graphical Interface where you can select columns you need 2 Add necessary tables 4 Save the View

31 Create View: IF EXISTS (SELECT name FROM sysobjects WHERE name = 'CourseData' AND type = 'V') DROP VIEW CourseData GO Creating Views using SQL A View is a virtual table that can contain data from multiple tables The Name of the View CREATE VIEW CourseData AS SELECT SCHOOL.SchoolId, SCHOOL.SchoolName, COURSE.CourseId, COURSE.CourseName, COURSE.Description FROM SCHOOL INNER JOIN COURSE ON SCHOOL.SchoolId = COURSE.SchoolId GO Using the View: select * from CourseData Inside the View you join the different tables together using the JOIN operator You can Use the View as an ordinary table in Queries : 31

32 Create Stored Procedure: IF EXISTS (SELECT name FROM sysobjects WHERE name = 'StudentGrade' AND type = 'P') DROP PROCEDURE StudentGrade OG CREATE PROCEDURE varchar(1) AS Stored Procedure A Stored Procedure is like Method in C# - it is a piece of code with SQL commands that do a specific task and you reuse it Procedure Name Input Arguments int select StudentId from STUDENT where StudentName Internal/Local Variables Note! Each variable starts select CourseId from COURSE where CourseName insert into GRADE (StudentId, CourseId, Grade) GO Using the Stored Procedure: execute StudentGrade 'John Wayne', 'SCE2006', 'B' SQL Code (the body of the Stored Procedure)

33 IF EXISTS (SELECT name FROM sysobjects WHERE name = 'CalcAvgGrade' AND type = 'TR') DROP TRIGGER CalgAvgGrade GO CREATE TRIGGER CalcAvgGrade ON GRADE FOR UPDATE, INSERT, DELETE AS float = StudentId from INSERTED Trigger A Trigger is executed when you insert, update or delete data in a Table specified in the Trigger. Create the Trigger: = AVG(Grade) from GRADE where StudentId update STUDENT set TotalGrade where StudentId GO Name of the Trigger Specify which Table the Trigger shall work on Specify what kind of operations the Trigger shall act on Internal/Local Variables Inside the Trigger you can use ordinary SQL statements, create variables, etc. SQL Code (The body of the Trigger) Note! INSERTED is a temporarily table containing the latest inserted data, and it is very handy to use inside a trigger

34 Summary DBMS Database Management System SQL Structured Query Language. A Database Computer Language designed for Managing Data in Relational Database Management Systems (RDBMS) ER Diagram Entity Relationship. Used for Design and Modeling of Databases. Specify Tables and relationship between them (Primary Keys and Foreign Keys)

35 References NTNU. (2013). TDT4140 Systemutvikling. Available: UiO. (2013). INF Systemutvikling. Available: O. Widder. (2013). geek&poke. Available: B. Lund. (2013). Lunch. Available: S. Adams. Dilbert. Available:

36 Hans-Petter Halvorsen, M.Sc. University College of Southeast Norway Blog: