Storage Limitations of Databases

These flashcards review key points about overall database size limits, data-type limits, table limits, storage planning considerations, and the importance of monitoring disk space from the lecture on storage limitations.

What are the three V’s affected by storage decisions when selecting a DBMS?

Velocity, Volume, and Variety

Why is storage capacity a key factor when choosing a DBMS?

Because different DBMSs have different storage offerings and limits, which impact performance, cost, reliability, and scalability.

Which popular open-source DBMSs have effectively unlimited database size, constrained only by hardware?

PostgreSQL, MariaDB, and MySQL

Name two commercial DBMSs that impose maximum caps on overall database size.

Oracle and Microsoft SQL Server (also SQLite).

How large can a Microsoft SQL Server Express database grow?

Up to 10 GB.

What is the size limit of Oracle’s free edition database?

12 GB.

What is the maximum size of a SQL Server Enterprise Edition database?

524 petabytes (PB).

How large can an Oracle Enterprise Edition database be?

Over 2,047 PB.

List three key factors (other than size) to evaluate when planning database storage.

Compliance & security, cost, data access patterns (others include redundancy, scalability, integration with infrastructure).

Give two symptoms that indicate a database server is running low on disk space.

Performance degradation and a sharp increase in failed transactions (others: application errors, unpredictable behavior, data corruption).

What is the ANSI SQL maximum size for VARCHAR data?

ANSI SQL does not define a limit.

What is the VARCHAR size limit in MySQL?

65,535 characters.

How large can a VARCHAR be in SQL Server?

Up to 2 GB.

State the VARCHAR limit in Oracle and PostgreSQL, respectively.

Oracle: 32,767 characters; PostgreSQL: 1 GB.

What is the CLOB size limit in MySQL?

216 bytes (per the lesson’s figure).

What is the CLOB limit in SQL Server?

2^31 − 1 bytes (~2 GB).

How large can a CLOB be in Oracle and PostgreSQL?

Oracle: 4 GB – 1 byte; PostgreSQL: 1 GB.

Which DBMS allows an unlimited table size and which limits MySQL tables to 256 TB?

Teradata allows unlimited table size; MySQL limits tables to 256 TB.

In SQL Server, what is the maximum table size?

A table can be as large as the database itself (up to 524,272 TB).

Why is monitoring available disk space critical for databases?

It prevents data corruption, transaction failures, and performance issues by alerting administrators before storage is exhausted.