Tuesday, April 14, 2009

SQL.. the beginning.

The first time I ever saw a database was in Paradox (database), in 1995. It was a huge learning curve, but I quickly learned what tables, columns and rows were. Then I learned how to build relationships and write SQL queries. (SQL is short for Structured Query Language)

This is how I then figured it was put together.

Every database has collection of one or more tables.
Tables are made up of rows and columns.
The rows contain the data and columns describe the format of the data, namely data type, for that column.

Imagine a telephone directory, information of a person’s first name, surname , address and ph number, this is how the basic table would be constructed:

Table: Phone_Directory

























FirstNameLastNameAddressPhone
JakeBlack123 Round Road, CA123 321-1234
SoniaCoke19 Sailfish Road, WA232 555-5555
MelBrown32 71st Ave, NY614 555-5432