Tabular or relational databases are those that can be organized in tables.
In opposition to tabular or relational databases there is NoSQL databases.
Database Normalization
You can read more about database normalization on this post.
12 Codd’s Rules
The 12 Codd’s rules were proposed by Codd that should follow ideally a relational table.
- Rule 0: The Foundation Rule
- Rule 1: Information Rule
- Rule 2: Guaranteed Access Rule
- Rule 3: Systematic Treatment of Null Values
- Rule 4: Active/Dynamic Online Catalog based on the relational model
- Rule 5: Comprehensive Data SubLanguage Rule
- Rule 6: View Updating Rule
- Rule 7: Relational Level Operation (High-Level Insert, Update and delete) Rule
- Rule 8: Physical Data Independence Rule
- Rule 9: Logical Data Independence Rule
- Rule 10: Integrity Independence Rule
- Rule 11: Distribution Independence Rule
- Rule 12: Non Subversion Rule
Relational Database Queries
Users and programs interact with relational databases through queries.
The most popular language for relational database queries is SQL.
SQL
Structured Query Language (SQL) is the most popular query language for relational databases.
You can read this post that is an introduction to SQL.
Database Issues
Dirty read n SQL occurs when a transaction reads data that has been modified by another transaction, but not yet committed. In other words, a transaction reads uncommitted data from another transaction, which can lead to incorrect or inconsistent results.
Non-repeatable read
Phantom read
List of Relational Databases
List of relational databases:
- PostgreSQL
- MariaDB
- MySQL
- SQLite
PostgreSQL
PostgreSQL is free and open source (FOSS), under a Postgres License.
Is developed by the PostgreSQL Global Development Group.
MariaDB
MariaDB is a free and open source software (FOSS), under a GPLv2 license.
It is a community-based project that was forked from MySQL when it was acquired by Oracle.
MySQL
MySQL is currently owned and developed by American company Oracle. MySQL was originally developed by Swedish company SQL AB, that was acquired by Sun Microsystems, that was acquired by Oracle.
MySQL Community is free and open source (FOSS), under a GPL license.
MySQL Enterprise is proprietary.
SQLite
SQLite is written in C.
It is public domain, so it is considered free and open source (FOSS).
CockroachDB
CockroachDB is a commercial database.
You might also be interested in…
- Introduction to Databases
- NoSQL Databases
External Links
- 12 Codd’s Rules
- Wikipedia community; “12 Codd’s rule”; Wikipedia