DBMS vs file system and types of keys
45 min · Intermediate
A database management system (DBMS) is software that stores data in a database and controls every read and write to it, so many users and programs can share the data safely. MySQL, PostgreSQL, Oracle and SQL Server are relational DBMSs; Section 12 (SQL & Database Design) teaches them hands-on, and this module revises the theory interviewers ask.
Topics in this lesson
- Problems with file systems: redundancy, inconsistency, concurrency
- Three-level architecture and data independence
- Super, candidate, primary, alternate, foreign and composite keys
- Worked example identifying keys in a table
- Interview questions with model answers
Interview questions this lesson answers
- What is a database and what is a DBMS?
- What is an RDBMS?
- Why use a DBMS instead of files?
- What is data redundancy, and why is it a problem?
- What is a database administrator's role?
- What is the difference between a schema and an instance?
- Explain the three-level architecture of a DBMS.
- What is data independence?
- Which is harder to achieve, logical or physical data independence?
- What are DDL, DML, DCL and TCL?
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