DBMS Basics - Interview Questions and Answers

  1. How do you communicate with an RDBMS?
    You communicate with an RDBMS using Structured Query Language (SQL).
  2. Define SQL and state the differences between SQL and other conventional programming Languages.
    SQL is a nonprocedural language that is designed specifically for data access operations on normalized relational database structures. The primary difference between SQL and other conventional programming languages is that SQL statements specify what data operations should be performed rather than how to perform them.
  3. Name the three major set of files on disk that compose a database in Oracle.

    There are three major sets of files on disk that compose a database. All the files are binary. These are

    1.) Database files
    2.) Control files
    3.) Redo logs

    The most important of these are the database files where the actual data resides. The control files and the redo logs support the functioning of the architecture itself. All three sets of files must be present, open, and available to Oracle for any data on the database to be useable. Without these files, you cannot access the database, and the database administrator might have to recover some or all of the database using a backup, if there is one.

  4. What is database Trigger?
    A database trigger is a PL/SQL block that can defined to automatically execute for insert, update, and delete statements against a table. The trigger can e defined to execute once for the entire statement or once for every row that is inserted, updated, or deleted. For any one table, there are twelve events for which you can define database triggers. A database trigger can call database procedures that are also written in PL/SQL.
  5. What are stored-procedures? And what are the advantages of using them?
    Stored procedures are database objects that perform a user defined operation. A stored procedure can have a set of compound SQL statements. A stored procedure executes the SQL commands and returns the result to the client. Stored procedures are used to reduce network traffic.
  6. What is Storage Manager?
    It is a program module that provides the interface between the low-level data stored in database, application programs and queries submitted to the system.