About the Structured Query Language (SQL)...


SQL commands are mainly categorised into four categories as:

DDL:  Data Definition Language
DQL:  Data Query Language
DML:  Data Manipulation Language
DCL:  Data Control Language
 

  1. DDL creates the tables with the required columns and with correct data types (numbers, dates, text strings, etc.)
     
  2. DQL reads (select) from one or more rows of one or more tables in the database.
     
  3. DML writes a new row (insert) to one or more tables in the database or updates existing fields in one more rows of a table. DML can also delete one or more rows in a table in the database.
     
  4. DCL authorizes (grants) the database user to perform DDL, DQL or DML operations or revoke the database user's privileges to perform database operations.


SQL is a common database language used in many Relational Database Management Systems (RDBMS) but it has a lot of dialects.

SQL-92 statements are interpreted by most RDBMS.

Read more about SQL here...  

 


Selecting the right database definition file during installation

n-gen.net CMS offers all database actions required compiled into one .sql file to get you started.
The install[yyyy-MM-dd].sql file contains all the table definitions (DDL) and initial data (DML) to make your n-gen.net CMS immediately operational in a few clicks.

If you are in doubt you should always select the newest install[yyyy-MM-dd].sql file!

Typically the installation files follow these naming conventions:

? install[yyyy-MM-dd].sql => an SQL-file that contains all you need for installing n-gen.net CMS,
    i.e. install[2020-06-06].sql
? install_addXXX[yyyy-MM-dd].sql => an SQL-file that contains new tables to be added to the database. This type of .sql files are only required for upgrading an existing installation of n-gen.net CMS.


Last updated 21-01-2025 11:35:34