1. IS6146 Databases for Management Information Systems Lecture 1: Introduction to IS6146 Rob Gleasure R.Gleasure@ucc.ie robgleasure.com

2. IS6146 Lecture times  13.00-15.00, Wednesday (KANE B10A) Contact me at  Ext 2503  Room 2.112  R.Gleasure@ucc.ie R.Gleasure@ucc.ie Website for this course  robgleasure.com robgleasure.com

3. IS6146 Module content and learning outcomes  Using databases (i.e. SQL)  Semistructured data (i.e. XML)  Unstructured data

4. IS6146 Course Assessment  Continuous assessment: 50 marks In-class exam* – 20 marks Group report* – 30 marks  Exam: 50 marks * To be confirmed

5. Database Management Systems A Database Management System (DBMS) is a software package designed to store and manage databases. This is different from a database file for several reasons  DBMS makes tables visible and generates reports  DBMS helps less technical users to use data efficiently  DBMS protects data from inconsistency and duplication due to multiple concurrent users  DBMS handles crash recovery  DBMS handles security and access control

6. Database Management Systems DBMS operates at the physical level This is where data handling becomes increasingly technical Physical model Logical model Conceptual model Management and business users Database administrators System analysts and designers

7. Database Management Systems DBMS are typically managed by a set Database Administrator, whose responsibilities include  Defining or refining logical schema in response to requirements  Granting appropriate access to users  Monitoring DBMS performance  Updating/changing DBMS software

8. Database Management Systems Other users will include  Application developers (write programs that need to access/modify data)  Sophisticated/specialised users (use DBMS directly to generate reports and assist business analysis)  Naïve users (use applications that access/modify data)

9. Examples of DBMS Oracle Large multi-user DBMS that excels at handling many clients requesting, accessing, and modifying data Popular in large organisations and cloud services due to scalability Very effective handling of concurrency, read consistency, parallel execution, and locking mechanisms MS Access Popular DBMS for small scale projects due to its relatively low cost and usability Imports and exports data to many formats commonly used in organisations, e.g. Excel, Outlook, SQL Server, Oracle Integrates easily with MS tools like VB, C# and.NET

10. Examples of DBMS MySQL Open source SQL database with free and paid versions Flexible and scalable Open source means lots of support and the potential for adaptability MS SQL Server Good performance XML integration Inclusion of try/catch queries

11. Comparison of DBMS from lab manuals (out of 5 stars) OracleMS AccessMySQLMS SQL Server Cost2.5453 Web friendly3333.5 Reliable4234.5 Complex3244.5 Security4333 Capacity3.5235 Flexibility3244 Technical fit3245 Ease of use34.53

12. Accessing a DBMS with SQL So once we have our data models in place and our DBMS set up, how do we get started using our data?  The SQL (pronounced like sequel) query language SQL (Structured Query Language) was introduced in the 70’s and has evolved since to add features such as  Compatibility with object-oriented programming  Compatibility with XML  Compatibility with XQuery

13. Accessing a DBMS with SQL

14. The Structure of SQL SQL can be divided into two parts:  The Data Manipulation Language (DML) Used to create, read, update and delete tuples (CRUD operations) Mostly used by application programmers and sophisticated/specialised users  The Data Definition Language (DDL) Used to define database structure (relation schemas) and data access control, as well as integrity constraints and views Mostly used by database administrator

15. Executing SQL in a DBMS

16. Accessing DBMS with SQL The basic syntax of SQL queries are as follows: COMMAND column_name1, column_name2, … FROM/SET/VALUES table_name1, table_name2, … WHERE column_name comparison_operator value; All statements in a semi-colon

17. The SQL Select statement The SELECT statement is used to retrieve data from a database into a result table, or result-set You can use an asterisk (*) instead of a column name if you wish to select all columns satisfying the criteria e.g. SELECT * FROM my_table;

18. The SQL Select statement Let’s open up an online example from W3Schools  http://www.w3schools.com/sql/trysql.asp?filename=trysql_select_all

19. The SQL Select statement Sometimes non-primary key columns may contain duplicate values - you can also use SELECT DISTINCT when you want to avoid duplicates in your result-set e.g. SELECT DISTINCT * FROM my_table;

20. The SQL Where clause A number of comparison operators are possible with the WHERE clause Examples  http://www.w3schools.com/sql/trysql.as p?filename=trysql_select_between_in  http://www.w3schools.com/sql/trysql.as p?filename=trysql_select_in OperatorDescription = Equal <>, != Not equal > Greater than < Less than >= Greater than or equal <= Less than or equal BETWEEN Between an range of numbers LIKE Searches for patterns IN When a specific value is sought

21. The ‘LIKE’ condition and Wildcards Sometimes we want to identify records based on slices of the data within a cell - we do this using wildcards and the LIKE condition Examples  http://www.w3schools.com/sql/trysql.asp?filename=trysql_select_wildcard_percent  http://www.w3schools.com/sql/trysql.asp?filename=trysql_select_wildcard_underscore  http://www.w3schools.com/sql/trysql.asp?filename=trysql_select_wildcard_charlist&ss=-1 WildcardDescription %A substitute for zero or more characters _A substitute for a single character [charlist]Sets and ranges of characters to match [^charlist] or [!charlist] Matches only a character NOT specified within the brackets

22. The SQL Where clause (continued) Numerous clauses can be combined with the keywords AND & OR e.g. SELECT * FROM my_table WHERE val1=‘true’ AND val2=‘false’; Complex clause can be creates by nesting clauses in parentheses e.g. SELECT * FROM my_table WHERE val1=‘true’ AND (val2=‘false’ OR val2=‘null’); Example  http://www.w3schools.com/sql/trysql.asp?filename=trysql_select_where_and_or

23. The SQL Order By keyword The ORDER BY keyword is used to sort the result-set e.g. SELECT * FROM my_table ORDER BY NAME; You may also specify whether you want the returned result-set to be sorted in ascending or descending order by using the keywords ASC or DESC e.g. SELECT * FROM my_table ORDER BY NAME DESC; Example  http://www.w3schools.com/sql/trysql.asp?filename=trysql_select_orderby_desc

24. Readings http://www.w3schools.com/sql http://www.tizag.com/sqlTutorial/