Bachelor of Information Technology Information Systems and Technology
Bachelor of Information Technology Information Systems and Technology - IT 1105 03. Organizing Data and Information Part IV 3. 1 Data Management Prabhajinie Jayabaalasundaram MBCS, MBA
Bachelor of Information Technology Information Systems & Technology IT 1105 03. Organizing Data and Information 3. 1 Data Management - Part IV Prabhajinie Jayabaalasundaram MBCS, MBA
IT 1105 Information Systems and Technology Intended Learning Outcomes After completing this session you should be able to; Identify different database models
IT 1105 Information Systems and Technology Last Lesson Database Management Software Database development Database interrogation Database maintenance Database structures Hierarchical structure Network structure
IT 1105 Information Systems and Technology Outline Database Structures Relational Structure Object-oriented structure Data Modeling Enterprise data modeling Relational Database Entity-relationship (ER) diagrams Types of Relationships
IT 1105 Information Systems and Technology Relational Structure In the relational model, all data elements within the database are viewed as being stored in the form of simple tables. Database management system packages based on the relational model can link data elements from various tables to provide information to users.
IT 1105 Information Systems and Technology Relational Structure Department Table Dept-No D-Name D-Location D-Manager Dept A Accounts 2 nd Floor Fernando Dept B HR 3 rd Floor Paul Dept C IT 1 st Floor Suren
IT 1105 Information Systems and Technology Relational Structure Employee Table E-No Emp-1 Emp-2 Emp-3 Emp-4 Emp-5 Emp-6 E-Name Siva John Wasim Perera E-Title Accountant Book Keeper HR Assistant Asst. Manager E-Salary 60, 000 40, 000 50, 000 70, 000 Dept. -No Dept. A Dept. B Peter System Analyst 65, 000 Dept. C Sneha Programmer 70, 000 Dept. C
IT 1105 Information Systems and Technology Object-oriented structure An object consists of data values describing the attributes of an entity plus the operations that can be performed upon the data. This encapsulation capability allows the object-oriented model to better handle more complex types of data (graphics, pictures, voice, text) than other database structures. The object-oriented model also supports inheritance; that is, new objects can automatically created by replicating some or all of the characteristics of one or more parent objects.
IT 1105 Information Systems and Technology Object-oriented structure In addition, multimedia web-based applications for the Internet and corporate intranets and extranets have become a major application area for object technology Object technology proponents argue that an object-oriented DBMS can work with complex data types such as document and graphic images, video clips, audio segments, and other subsets of Web pages much more efficiently than relational database management systems. However, major relational DBMS vendors have countered by adding object-oriented modules to their relational software.
IT 1105 Information Systems and Technology Object-oriented structure Current Account Object Attributes Credit Amount Operations Deposit Withdraw (500) Bank Account Object Attributes Customer Balance Interest Operations Deposit (1000) Withdraw (500) Savings Account Object Attributes No. of withdrawals No. of Deposits Operations Calculate interest paid
IT 1105 Information Systems and Technology Question Relational databases (a) help to identify relationships between different entities. (b) cannot support concurrent users at all. (c) are extremely difficult to use and therefore are used only by organisations with internal support staff. (d) are most effective in storing, accessing and manipulating complex data such as images and graphics (e) represent data in rows.
IT 1105 Information Systems and Technology Answer Relational databases (a) help to identify relationships between different entities. (b) cannot support concurrent users at all. (c) are extremely difficult to use and therefore are used only by organisations with internal support staff. (d) are most effective in storing, accessing and manipulating complex data such as images and graphics (e) represent data in rows.
IT 1105 Information Systems and Technology Question Which of the following is a/are data model(s) which help(s) to define relationships between data? (a) Relational (b) Hierarchical (c) Horizontal (d) Virtual (e) Network
IT 1105 Information Systems and Technology Answer Which of the following is a/are data model(s) which help(s) to define relationships between data? (a) Relational (b) Hierarchical (c) Horizontal (d) Virtual (e) Network
IT 1105 Information Systems and Technology Data Modeling One of the tools database designers use to show the logical relationships among data is a data model. A data model is a diagram of entities and their relationships. Data modeling usually involves understanding a specific business problem and analyzing the data and information needed to deliver a solution. When done at the level of the entire organization this is called enterprise data modeling.
IT 1105 Information Systems and Technology Enterprise data modeling is an approach that starts by investigating the general data and information needs of the organization at the strategic level, and then examines more specific data and information needs for the various functional areas and departments within the organization. Various models have been developed to help managers and database designers analyze data and information needs. An entity-relationship diagram is an example of such a data model.
IT 1105 Information Systems and Technology Entity-relationship (ER) diagrams use basic graphical symbols to show the organization of and relationships between data. In most cases, boxes in ER diagrams indicate data items or entities contained in data tables, and diamonds show relationships between data items and entities. In other words, ER diagrams show data items in tables (entities) and the ways they are related.
IT 1105 Information Systems and Technology Entity-relationship (ER) diagrams ER diagrams help ensure that the relationships among the data entities in a database are correctly structured so that any application programs developed are consistent with business operations and user needs. In addition, ER diagrams can serve as reference documents after a database is in use. If changes are made to the database, ER diagrams help design them.
IT 1105 Information Systems and Technology Entity-relationship (ER) diagrams Figure Have to draw in white board
IT 1105 Information Systems and Technology Points to note A relationship is established between two database tables when one table has a foreign key that references the primary key of another table. This is the basic concept behind the term relational database. A primary key uniquely identifies each record in the table. It is a type of candidate key that is usually the first column in a table and can be automatically generated by the database to ensure that it is unique. A foreign key is another candidate key (not the primary key) used to link a record to data in another table.
IT 1105 Information Systems and Technology Relational Structure Department Table Dept. -No Dept. A D-Name Accounts D-Location 2 nd Floor D-Manager Fernando HR 3 rd Floor Paul IT 1 st Floor Suren Dept. B Dept. C
IT 1105 Information Systems and Technology Relational Structure Employee Table E-No E-Name Emp-1 Siva Emp-2 John Emp-3 Wasim Perera Emp-4 Peter Emp-5 Emp-6 Sneha E-Title Accountant Book Keeper HR Assistant Asst. Manager E-Salary 60, 000 40, 000 50, 000 70, 000 Dept. -No Dept. A Dept. B System Analyst 65, 000 Dept. C Programmer 70, 000 Dept. C
IT 1105 Information Systems and Technology Types of Relationships – Relational Database Using foreign keys, or other candidate keys, you can implement three types of relationships between tables: • One-to-one: This type of relationship allows only one record on each side of the relationship. • One-to-many: A one-to-many relationship allows a single record in one table to be related to multiple records in another table. • Many-to-many: This is a complex relationship in which many records in a table can link to many records in another table.
IT 1105 Information Systems and Technology Question ‘Student’ is one of the files in a relational database that contains personal data of students in a college. Which of the following statements is/are TRUE about the ‘Student’ file? (a) The attributes of the student file could be 1105, Dulmith, Ekanayaka, 30 Temple Lane, Nawala. (b) The primary key of this file could be the student number. (c) Each row of the file will have data of two students. (d) A collection of different attributes are represented by a column. (e) The ‘Name of a Student’ could be represented by alpha numeric data type.
IT 1105 Information Systems and Technology Answer ‘Student’ is one of the files in a relational database that contains personal data of students in a college. Which of the following statements is/are TRUE about the ‘Student’ file? (a) The attributes of the student file could be 1105, Dulmith, Ekanayaka, 30 Temple Lane, Nawala. (b) The primary key of this file could be the student number. (c) Each row of the file will have data of two students. (d) A collection of different attributes are represented by a column. (e) The ‘Name of a Student’ could be represented by alpha numeric data type.
IT 1105 Information Systems and Technology Question Identify the correct statement/s about the relational Database, its keys and relationships a) A relationship is established between two database tables when one table has a foreign key b) A primary key uniquely identifies each record in the table. c) Primary key and the foreign key are candidate keys d) A foreign key uniquely identifies each record in the table e) A foreign key is used to link a record to data in another table.
IT 1105 Information Systems and Technology Answer Identify the correct statement/s about the relational Database, its keys and relationships a) A relationship is established between two database tables when one table has a foreign key b) A primary key uniquely identifies each record in the table. c) Primary key and the foreign key are candidate keys d) A foreign key uniquely identifies each record in the table e) A foreign key is used to link a record to data in another table.
IT 1105 Information Systems and Technology Summery Database Structures Relational Structure Object-oriented structure Data Modeling Enterprise data modeling Relational Database Entity-relationship (ER) diagrams Types of Relationships
Bachelor of Information Technology Information Systems & Technology IT 1105 03. Organizing Data and Information 3. 1 Data Management - Part IV Prabhajinie Jayabaalasundaram MBCS, MBA
Bachelor of Information Technology Information Systems and Technology - IT 1105 03. Organizing Data and Information Part IV 3. 1 Data Management Prabhajinie Jayabaalasundaram MBCS, MBA
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