important question on Database Management System(DBMS)

5) What are five main functions of a database administrator?
Answer: Five main functions of a database administrator are:

• To create the scheme definition.
• To define the storage structure and access methods.
• To modify the scheme and/or physical organization when necessary.
• To grant authorization for data access.
• To specify integrity constraints.

6)List seven programming languages that are procedural and two that are non-procedural. Which group is easier to learn and use? Explain your answer.

Answer: Programming language classification:

• Procedural: C, C++, Java, Basic, Fortran, Cobol, Pascal.
• Non-procedural: Lisp and Prolog.

Note: Lisp and Prolog support some procedural constructs, but the core of both
these languages is non-procedural.
In theory, non-procedural languages are easier to learn, because they let the
programmer concentrate on what needs to be done, rather than how to do it. This is not always true in practice, especially if procedural languages are learned first.

7) List six major steps that you would take in setting up a database for a particular enterprise.
Answer: Six major steps in setting up a database for a particular enterprise are:

• Define the high level requirements of the enterprise (this step generates a
  document known as the system requirements specification.)
• Define a model containing all appropriate types of data and data relation-
  ships.
• Define the integrity constraints on the data.
• Define the physical level.
• For each known problem to be solved on a regular basis (e.g., tasks to be
  carried out by clerks or Web users) define a user interface to carry out the
  task, and write the necessary application programs to implement the user
  interface.
• Create/initialize the database.

8) Consider a two-dimensional integer array of size n × m that is to be used in your favorite programming language. Using the array as an example, illustrate the difference (a) between the three levels of data abstraction, and (b) between a schema and instances.
Answer: Let tgrid be a two-dimensional integer array of size n × m.

• The physical level would simply be m × n (probably consecutive) stor-
  age locations of whatever size is specified by the implementation (e.g.,
  32 bits each).
• The conceptual level is a grid of boxes, each possibly containing an integer, which is n boxes high by m boxes wide.
• There are 2 m×n possible views. For example, a view might be the entire
  array, or particular row of the array, or all n rows but only columns 1
  through i.
• Consider the following Pascal declarations:
  type tgrid = array[1..n, 1..m] of integer;
  var vgrid1, vgrid2 : tgrid
  Then tgrid is a schema, whereas the value of variables vgrid1 and vgrid2
  are instances.
• To illustrate further, consider the schema array[1..2, 1..2] of integer. Two
  instances of this scheme are: