What is formatting and validating field data in database management system? Give an example to illustrate.

Formatting controls how data looks; Validation controls what data is allowed. Both improve readability and prevent wrong entries in government databases where one wrong digit can misplace salary or citizenship records.

1. Formatting field data: Formatting sets display style without changing stored value. Set in table design → Format property.

Examples in MS-Access:

• Date: 15-Jan-2024 vs 15/01/2024 — same date, different look.
• Currency: 50000 displays as Rs. 50,000.00.
• Text: > forces UPPERCASE, < forces lowercase — useful for names.
• Phone: Input mask 09\-999999999 shows consistent mobile format.

2. Validating field data: Validation is a rule that rejects invalid data during entry.

Common validation methods:

• Required: Field cannot be left blank. Example: CitizenshipNo = Required Yes.
• Validation Rule: Condition. Example: >=0 And <=100 for Marks; >=18 for Age; Like "98*" for Nepali mobile starting with 98.
• Validation Text: Message shown on error. Example: “Marks must be 0–100”.
• Input Mask: Fixed pattern. Example: 0000-00-00 for YYYY-MM-DD date.
• Lookup/List: Choose only from list. Example: Gender = Male/Female/Other; District from 77 districts list.

Illustration: In a Staff table, set Age field: Validation Rule >=18 And <=60, Validation Text “Age must be 18–60 for service”. If clerk types 15, Access blocks save and shows the message. This prevents under-age entry at the source instead of fixing later in reports.