DBMS Basics - Interview Questions and Answers

  1. What is Data Storage - Definition Language?
    The storage structures and access methods used by database system are specified by a set of definition in a special type of DDL called data storage-definition language.
  2. What is DML (Data Manipulation Language)?
    This language that enable user to access or manipulate data as organised by appropriate data model.
    1. Procedural DML or Low level: DML requires a user to specify what data are needed and how to get those data.
    2. Non-Procedural DML or High level: DML requires a user to specify what data are needed without specifying how to get those data.
  3. What is DML Compiler?
    It translates DML statements in a query language into low-level instruction that the query evaluation engine can understand.
  4. What is Query evaluation engine?
    It executes low-level instruction generated by compiler.
  5. What is DDL Interpreter?
    It interprets DDL statements and record them in tables containing metadata.
  6. What is Record-at-a-time?
    The Low level or Procedural DML can specify and retrieve each record from a set of records. This retrieve of a record is said to be Record-at-a-time.