Files vs Databases


Differences

Files Databases
Only one person at a time ca change it Thousands of users can change at same time
Limited Undo Can Undo to any date and time
Must backup entire file Have option to backup changes only
Cannot detected corrupted data Detects and Fixes corrupted data
Has no integrity Has integrity - checks the relationships between tables
Security on the File Security on Individual Rows and Columns

Data Types

Data Types Maximum Size Example Notes
STANDARD CHAR 256 Name CHAR(30) Fixed Size
VARCHAR 4096 Comments VARCHAR(400) Variable Size
(NCHAR, NVARCHAR) UNICODE - ASIAN Languages Takes twice the space
NUMERIC 32 Customer# NUMERIC(6) - int Amount NUMERIC(8,2) - decimal
DATETIME Hired On DateTime
MICROSOFT int, long, short, float, double, decimal
string, text
image, binary (up to 4Gb)
XML Don't use microsoft's types