1. Database uses a number of keys. Explain giving the difference between a candidate key and a super key[4]2. A hospital is organised into a number of wards. Each ward has a ward number and a name recorded, along with a number of beds in that ward. Each ward is staffed by nurses. Nurses have their staff number and name recorded, and are assigned to a single ward. Each patient in the hospital has a patient identification number, and their name, address and date of birth are recorded. Each patient is under the care of a single consultant and is assigned to a single ward. Each consultant is responsible for a number of patients. Consultants have their staff number, name and specialism recorded.Draw a well annotated ERD basing on the above details. [11]3. Describe each of the following types of user interface and give an example of an application where it might be used.(i) Form based. [3](ii) Menu based. [3](iii) Command line. [3]4. (a) When software is written, the code will probably contain errors. Describe any two methods or tools available for identifying program errors. [4] (b) Describe two methods of making the code of a piece of software more understandable to other programmers. [4]5. (a) State the meaning of the terms(i) source code,(ii) object codeand state the process that connects them. [3](b) Explain how this process can be used to check program code written by a programmer [2]6. Describe the following terms as used in databasesa. Degreeb. Cardinalityc. Relationship[3]7. State and explain any two components of DBMS environment [4]8. An integer is defined as an unsigned integer or a signed integer. An unsigned integer is one or an unlimited set of digits, where a digit is defined as: 0|1|2|3|4|5|6|7|8|9Use BNF to define [4]9. (a) Explain the term parameter[2](b) With reference to programming, describe passing by value and passing by reference [2](c) Design a VB6.0 to illustrate passing a parameter by value or by reference. The program should accept a single value in a sub procedure and display the result. The function to be called must add the accepted value to 2[9]10. Give any reasons why games are written in assembly language[1]11. Explain the differences between lexical analysis stage and syntax analysis stage in the compilation process of a high level language program[4]12. What is the difference between a fixed length and variable length string? Show how fixed and variable strings are declared in VB6.0 [3]13. Explain the function of a loader in the running of the final program[2]14. Programs written in high level languages can either be compiled or interpreted. What are the differences between an interpreter and a compiler? [3]15. Design a VB6.0 program to display the middle character of each of the five strings entered by the user. The string and its middle character must be displayed in a list box together with the appropriate narrations to make the output meaningful. [10]16. Design a VB6.0 or VB.Net program which calculates the square roots of all the numbers the user has entered in a single session. The actual number of numbers to be entered by the user are not known. The results are displayed on the form [16]