Chapter 1 - Lesson 5 (Part 1)

Basic ICT tutorials (Information Communication Technology)

2 Jun 202009:20

Summary

TLDRThe video discusses various types of validation rules and verification in computer systems, explaining why validation is necessary. It covers different checks such as presence, range, type, length, format, and lookup checks. These rules ensure that data entered into a system is appropriate, though not necessarily correct. Examples include verifying if required fields are filled (presence check), ensuring data falls within certain limits (range check), or checking if data matches a specific format (format check). The video emphasizes the importance of validating input to maintain data integrity.

Takeaways

✅ Validation ensures that data input into a system is sensible and conforms to defined rules.
📅 An example of validation: A railway season ticket is valid until its expiry date, and this date is checked during validation.
❌ When data is invalid or doesn't conform to rules, it is rejected, and an error message is presented.
🔎 Presence check ensures that necessary data is entered; if not, an error message prompts the user to input the missing data.
📧 Example of a presence check: A contact form that requires an email address but doesn't check if it's formatted correctly.
🔢 Range check ensures that data falls between defined limits, like age being between 18 and 28 for a survey.
📏 Type check ensures that data is of the correct type, such as age being an integer or a grade being text.
🔐 Length check verifies that data is of a specific length, such as a password needing at least 8 characters.
🔤 Format check ensures data follows a required pattern, like an email address having an '@' symbol and proper structure.
📂 Lookup check tests whether data exists in a predefined list, like validating gender as 'male' or 'female'.

Q & A

What is the purpose of validation in a computer system?
-Validation ensures that data entered into a computer system is sensible and conforms to predefined rules, ensuring it is fit for use.
Can you give an example of a situation where validation is important?
-An example is a railway season ticket. The ticket has an expiry date, and the validation rule ensures that the ticket is used before it expires.
What happens when data is entered correctly or incorrectly in a validation check?
-If data conforms to the validation rules, it will be accepted. If it does not, the data will be rejected, and an error message will be displayed.
What is a presence check, and how does it work?
-A presence check ensures that data is entered into a required field. If data is missing, the user receives an error message prompting them to enter the required data.
Can you provide an example of a presence check?
-An example is a login form where you must enter both a username and a password. If the password is left blank, an error message will appear asking the user to input it.
What is a range check, and how does it differ from a limit check?
-A range check ensures that data falls within a specific range, with both a lower and upper boundary. A limit check has only one boundary, ensuring the data meets a single condition, such as being above or below a particular value.
Can you give an example of a range check?
-A range check could be used for the number of students in a class, where the acceptable range might be between 5 and 28.
What is a type check, and why is it important?
-A type check ensures that the data entered is of the correct data type. For example, an age must be an integer, and a price must be numerical. This prevents users from entering incorrect data formats.
What is a length check, and can you provide an example?
-A length check ensures that the data entered is of a specific length. For example, a password might be required to be at least 8 characters long.
What is a format check, and how does it function?
-A format check ensures that data follows a specific pattern or format. For example, an email address must include an '@' symbol followed by a domain. If the data doesn't match the required format, it will be rejected.
What is a lookup check, and when would it be used?
-A lookup check verifies whether the data entered exists in a predefined list or file. For example, when selecting a gender, the system might allow only 'Male' or 'Female' as valid options.

Outlines

00:00

🔍 Introduction to Validation and Verification in Data Entry

This paragraph introduces the topic of validation and verification rules in data entry. It explains the importance of validation when data is input into a system, ensuring that data follows specific rules to be considered sensible. An example is given using a railway season ticket where the expiry date serves as a validation criterion. The process ensures that data entered is valid before further processing, such as rejecting incorrect data with an error message.

05:02

✅ Presence Check in Data Validation

The paragraph discusses presence checks, a validation rule used to ensure that essential data is entered by the user. Examples include login forms where users must provide both a username and password. If a field like the password is left blank, an error message prompts the user to enter the missing data. However, presence checks only confirm that data is entered, not whether it is accurate, as demonstrated by accepting incorrect formats such as nonsensical email addresses.

📊 Range and Limit Checks Explained

This paragraph elaborates on range and limit checks. A range check ensures that data falls within a defined range with both upper and lower boundaries, such as the age of students in a class being between 5 and 28. A limit check, on the other hand, deals with one boundary condition. Examples include minimum age limits for surveys, where only the lower boundary (e.g., age 18) matters. Both types of checks ensure the data is within acceptable parameters before being accepted.

🔠 Type Check: Ensuring Correct Data Types

Here, the focus is on type checks, which verify that the data entered matches the expected data type. For instance, an age must be an integer, a grade must be a letter, and a date of birth must be in date format. This ensures that inputs adhere to predefined types, preventing errors in data processing.

🔢 Length Check: Controlling Data Input Length

This section describes length checks, a validation rule used to ensure that data is of a specified length or falls within a range of lengths. Common examples include setting minimum character limits for passwords (e.g., 8 characters or more) and requiring certain fields like product codes to be of a specific length. This rule ensures that inputs meet the necessary size criteria.

🔤 Format Check: Verifying Data Patterns

The paragraph explains format checks, which validate that the data follows a specific pattern or format. For example, email addresses must contain an '@' symbol, and student IDs must follow a predefined sequence of numbers and letters. If the data does not match the expected pattern, it is rejected, ensuring consistency in the format of inputs.

🔎 Lookup Check: Cross-Referencing Input with Accepted Data

This paragraph discusses lookup checks, a validation process that verifies whether the entered data exists within a predefined list of acceptable values. For instance, when entering gender, the system cross-references the input with a stored list of valid options like 'male' or 'female.' If the input doesn't match any of the acceptable values, the system prompts an error. Another example involves grading systems where only predefined grades such as 'P', 'M', or 'D' are accepted.

Mindmap

Keywords

💡Validation

Validation refers to the process of checking data to ensure that it conforms to predefined rules or criteria. In the video, it is discussed as a necessary step when data is entered into a computer system to ensure the data is sensible. For example, a railway season ticket is considered valid only before its expiration date. The main purpose of validation is to ensure that entered data meets the system’s requirements, though it does not guarantee that the data is correct.

💡Presence Check

A presence check is a type of validation rule that ensures data is entered into a field before submission. In the video, an example is given of a login form where a user might forget to enter their password, and the system would prompt them to do so. The presence check only ensures that something is entered, not whether the entered data is correct.

💡Range Check

A range check ensures that entered data falls within a predefined range of acceptable values. The video explains this with an example of an opinion poll where respondents must be at least 18 years old. The range check would ensure the age is between defined lower and upper limits. For instance, the number of students in a class might be validated to be between 5 and 28.

💡Limit Check

A limit check is a form of validation that ensures data meets a single boundary condition, either a minimum or maximum value. The video describes a limit check as a situation where there is only one boundary involved, such as requiring the age of a person to be at least 18 years. This contrasts with a range check, which involves both upper and lower boundaries.

💡Type Check

A type check ensures that the data entered is of the correct data type (e.g., integer, text, date). In the video, examples include ensuring that an age is entered as a number and not as text, or that a price must be numeric. The type check is important to prevent data from being entered in an invalid form, such as entering letters where numbers are required.

💡Length Check

A length check ensures that the data entered has the correct number of characters. The video mentions the example of a password, where the system might require the password to be at least 6 characters long. Another example given is that a product code must be between 4 and 6 characters long.

💡Format Check

A format check validates that data matches a specified pattern or format. For example, the video describes how an email address must include an ‘@’ symbol with characters before and after it. The format check ensures that the data entered follows the required pattern, such as ensuring a student ID has four numbers followed by two letters.

💡Lookup Check

A lookup check validates entered data against a predefined list of acceptable values. The video provides an example where gender can only be entered as 'male' or 'female.' If the user enters a value outside of this predefined list, such as a different word, the system will return an error. This type of validation ensures that only specific, predefined options are accepted.

💡Error Message

An error message is a notification that informs users when their data fails to meet validation rules. In the video, it is mentioned that if data does not conform to the validation rules, the user will see an error message prompting them to correct the issue. For example, if a required field is left empty, an error message will ask the user to fill it in.

💡Verification

Verification is the process of ensuring that entered data is correct, often through double-checking or confirming accuracy. Although not the primary focus of the video, verification is briefly mentioned as part of ensuring the overall correctness of data, as opposed to just checking that it conforms to certain rules as in validation.

Highlights

Validation ensures that data is sensible and conforms to defined rules, but it does not guarantee the data is correct.

An example of validation: a railway season ticket is valid until its expiry date; using it after expiration makes it invalid.

Presence check: Ensures that data is entered. For example, leaving the password field empty when logging in will prompt an error message.

Presence check only ensures that data is entered, not that the data is correct or in the proper format.

Range check: Ensures data is within a defined range. For example, a survey respondent must be at least 18 years old.

Limit check: A form of range check where there is only one boundary. For instance, grades must be less than or equal to 'E'.

Range check example: The number of students in a class should be between 5 and 28.

Type check: Ensures the data matches a defined data type. For example, an age must be an integer, and a price must be numerical.

Length check: Ensures data is of a defined length or within a range. Example: a password must be at least 8 characters long.

Format check: Ensures data matches a specific format, such as an email address including the '@' symbol followed by additional characters.

Format check example: A student ID must consist of four numbers followed by two letters.

Lookup check: Validates data by checking if it exists in a predefined list. Example: Gender must be either 'Male' or 'Female'.

Lookup check can also be used for qualification grades, ensuring values like 'Pass', 'Merit', or 'Distinction' are entered.

Validation rules help prevent incorrect data from being accepted by a computer system, maintaining data integrity.

Each validation rule, such as presence, range, type, length, format, and lookup checks, plays a crucial role in ensuring data quality and reliability.