1. Define each of the following terms: i.Entity: (2 Marks) ii. Entity type: (2 Marks) iii. Entity set. (2 Marks) 2. State the three levels of data abstraction in Database Management Systems (3 Marks) 3. Describe three keys that can be used in database. (6 Marks) 4. Explain two types of Data Independence in databases. (4 Marks) 5. Explain the term data testing as used in a database. (2 Marks) 6. Explain two reasons for performing database lesting. (3 Marks) 7. Mary developed a database for a company Outline the four key stages she could have followed when testing this database (4 Marks) 8. Mike designed a database using an Entity Relationship Diagram (ERD). Using symbols; describe three connotations of ERD he could use. (6 Marks) 9. There are four most basic operations in database which are the backbone for interacting with database. State two of these database operations. (2 Marks) 10. With the aid of an example in each case, describe three components of a database system. (4 Marks) SECTION B (60 MARKS) Answer any THREE questions from this section. 11. a) Define the term database. (2 Marks) b) Differentiate between field and record as used in databases (2 Marks) c) Explain the following as used in relational database model: (10 Marks) i) Table; ii) Tuple; iii) Attributes; iv) Relation schema; v) Domain. d) Explain the three types of relationships in databases (6 Marks) 12. a) Explain six characteristics of Database Management System. (12 Marks) b) A company has installed a database system for its'operations. Explain four benefits accrued from its use. (8 Marks) 13. a) Data Definition Language is used to bring objects into existence Discuss five database objects. (10 Marks) b) Discuss five types of database security. (10 Marks) 14. a) Highlight four factors considered when choosing the type of database software to adopt. (4 Marks) b) The ACID properties of data transactions provide a mechanism to ensure the correctness and consistency of data in a database. Explain each of these four properties. (8 Marks) c) Databases are designed based on various data models. Discuss four database models.

1. Definitions:<br /> i. **Entity**: An entity is a real-world object or concept that can be distinctly identified and has attributes. For example, in a university database, a student can be considered an entity.<br /> <br /> ii. **Entity Type**: This refers to a collection of entities that share common properties or characteristics. For instance, "Student" is an entity type that includes all students as its instances.<br /> <br /> iii. **Entity Set**: An entity set is a collection of similar types of entities. For example, all students in a university form the entity set for the entity type "Student."<br /><br />2. Three levels of data abstraction in Database Management Systems:<br /> - Physical Level<br /> - Logical Level<br /> - View Level<br /><br />3. Three keys used in databases:<br /> - **Primary Key**: A unique identifier for each record in a table.<br /> - **Foreign Key**: A field (or collection of fields) in one table that uniquely identifies a row of another table.<br /> - **Candidate Key**: A minimal super key; it can uniquely identify any database record without referring to any other data.<br /><br />4. Two types of Data Independence:<br /> - **Logical Data Independence**: The capacity to change the conceptual schema without having to change external schemas or application programs.<br /> - **Physical Data Independence**: The ability to change the internal schema without having to change the conceptual schema.<br /><br />5. Data Testing in a database involves verifying that the data stored in the database is accurate, consistent, and meets the specified requirements.<br /><br />6. Two reasons for performing database testing:<br /> - To ensure data integrity and accuracy.<br /> - To verify that the database performs optimally under various conditions.<br /><br />7. Four key stages Mary could have followed when testing the database:<br /> - Requirement Analysis<br /> - Test Planning<br /> - Test Case Development<br /> - Test Execution and Bug Reporting<br /><br />8. Three connotations of ERD symbols:<br /> - **Rectangle**: Represents an entity.<br /> - **Ellipse**: Represents an attribute.<br /> - **Diamond**: Represents a relationship between entities.<br /><br />9. Two basic operations in databases:<br /> - **Insert**: Adding new data to the database.<br /> - **Delete**: Removing existing data from the database.<br /><br />10. Three components of a database system:<br /> - **Database Engine**: Manages data storage, retrieval, and update. Example: MySQL engine.<br /> - **Database Schema**: Defines the structure of the database. Example: Tables and relationships in a relational database.<br /> - **Query Processor**: Interprets and executes database queries. Example: SQL query execution.<br /><br />11. a) A database is an organized collection of structured information or data, typically stored electronically in a computer system.<br /><br /> b) Difference between field and record:<br /> - **Field**: A single piece of data or attribute of a record. Example: "Name" in a student record.<br /> - **Record**: A complete set of fields representing a single entity. Example: All details of a student.<br /><br /> c) Relational database model terms:<br /> i) **Table**: A collection of related data entries consisting of rows and columns.<br /> ii) **Tuple**: A single row in a table, representing a single record.<br /> iii) **Attributes**: Columns in a table, representing data fields.<br /> iv) **Relation Schema**: The structure defining a relation, including its name, attributes, and their types.<br /> v) **Domain**: The set of permissible values for an attribute.<br /><br /> d) Three types of relationships in databases:<br /> - One-to-One<br /> - One-to-Many<br /> - Many-to-Many<br /><br />12. a) Six characteristics of Database Management System:<br /> - Data Abstraction<br /> - Data Independence<br /> - Efficient Data Access<br /> - Data Integrity and Security<br /> - Concurrent Access and Recovery<br /> - Data Administration<br /><br /> b) Four benefits of using a database system:<br /> - Improved data sharing<br /> - Enhanced data security<br /> - Better data integration<br /> - Minimized data inconsistency<br /><br />13. a) Five database objects in Data Definition Language:<br /> - Tables<br /> - Views<br /> - Indexes<br /> - Sequences<br /> - Synonyms<br /><br /> b) Five types of database security:<br /> - Authentication<br /> - Authorization<br /> - Encryption<br /> - Backup and Recovery<br /> - Auditing<br /><br />14. a) Four factors when choosing database software:<br /> - Scalability<br /> - Compatibility<br /> - Cost<br /> - Support and Community<br /><br /> b) ACID properties:<br /> - **Atomicity**: Ensures transactions are fully completed or not at all.<br /> - **Consistency**: Ensures data remains consistent before and after a transaction.<br /> - **Isolation**: Ensures transactions do not interfere with each other.<br /> - **Durability**: Ensures committed transactions persist even in case of system failure.<br /><br /> c) Four database models:<br /> - Hierarchical Model<br /> - Network Model<br /> - Relational Model<br /> - Object-Oriented Model