Validation rules and accurate data

A field can store whole-number counts, but this form only allows counts from 1 to 12 inclusive. Is 20 acceptable under that extra rule?

Separate the kind of value from the permitted range

Read the whole input contract

Validation checks whether an entry meets stated rules. It does not by itself establish that the entry is true

First remove surrounding spaces, then check in this order and stop at the first failure: presence requires at least one character; format requires only digits 0 to 9; range requires the resulting numerical value to be from 1 to 12 inclusive. Leading zeros are allowed

Presence, format and range answer different questions: is anything supplied, are its characters permitted, and is its numerical value allowed?

These are one demonstration form's rules, not universal rules for every computer system

An empty entry stops first

A demonstration count field uses these fixed validation rules

First remove surrounding spaces, then check in this order and stop at the first failure: presence requires at least one character; format requires only digits 0 to 9; range requires the resulting numerical value to be from 1 to 12 inclusive. Leading zeros are allowed

Entered text: "". The quotation marks delimit the entry and are not part of it

Which is the first failed check, or does the entry pass all three?

After removing surrounding spaces, no characters remain

Presence fails first, so later checks are not reached

Present does not mean correctly formatted

A demonstration count field uses these fixed validation rules

First remove surrounding spaces, then check in this order and stop at the first failure: presence requires at least one character; format requires only digits 0 to 9; range requires the resulting numerical value to be from 1 to 12 inclusive. Leading zeros are allowed

Entered text: "two". The quotation marks delimit the entry and are not part of it

Which is the first failed check, or does the entry pass all three?

At least one character is present, so presence passes

The entry two contains a character other than a digit 0 to 9, so format fails before range is checked

Check the permitted characters

Inclusive endpoints belong to the range

From 1 to 12 inclusive includes both 1 and 12. Zero and 13 lie outside that interval

Range is reached only after presence and format pass. A word is not first rejected by range when format has already failed

This form allows leading zeros, so 04 is checked as the numerical value 4. Another form could declare a different rule

A decimal entry such as 3.0 has the value 3, but its dot violates this form's digits-only format. A question asking only for a numeric value may instead accept equivalent forms

Removing surrounding spaces makes an entry containing only spaces empty; it does not remove spaces between digits

Test the lower endpoint

Test just above the upper endpoint

Apply the stated zero rule

Acceptance and truth are different questions

A permitted entry can still be an inaccurate description of reality. For example, 4 meets the form's rules even if a trusted recount finds 9 items

Check validation against the rules, then check accuracy against the supplied trusted evidence

For these tasks, the recount is explicitly trusted. In real work, the quality of the reference evidence would also need checking

Do not replace a known count with an invented allowed value just to make a form accept it

Valid format, different count

A demonstration count field uses these fixed validation rules

First remove surrounding spaces, then check in this order and stop at the first failure: presence requires at least one character; format requires only digits 0 to 9; range requires the resulting numerical value to be from 1 to 12 inclusive. Leading zeros are allowed

Entered text: "4". The quotation marks delimit the entry and are not part of it

A trusted recount found 9 items. Treat that observation as correct for this task; the form still uses the stated 1 to 12 rule even if the actual count lies outside it

Which statement correctly describes both validation and agreement with the trusted count?

Characters are present and every character is a digit, so presence and format pass

The numerical value 4 lies from 1 to 12 inclusive, so all three checks pass

The entered numerical value 4 differs from the trusted count 9

Therefore, the entry passes validation but differs from the trusted count

Check two independent conclusions

A permitted value can be wrong

A rejected entry may expose a rule mismatch

A trusted count of zero can be real even if a form requires at least one item. The rule and the observation then disagree

Preserve the trusted evidence and use the system's authorised exception or rule-review process. Do not invent a count of one

Rejected but consistent with the recount

Keep both findings

Apply rules, then compare evidence

Follow the declared normalisation, check order, character rules and inclusive limits

A presence check is not a format check, and a format check is not a range check

Passing validation is not proof of accuracy; rejecting an entry is not proof that the real observation is impossible

These finite decisions practise interpretation. Creating, testing and using a real spreadsheet or database validation process requires a separate practical task