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Different key fields for different cases More to Learn A key field is a field that can be used to uniquely identify one specific record from other records.

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Presentation on theme: "Different key fields for different cases More to Learn A key field is a field that can be used to uniquely identify one specific record from other records."— Presentation transcript:

1 Different key fields for different cases More to Learn A key field is a field that can be used to uniquely identify one specific record from other records. The data in a key field is unique to a specific record. A good key field for a particular database table may be improper for others. For example: The mobile telephone number can be used as a key field for a membership table of a boutique chain. This key field can be used to uniquely identify each member. It is not the case for a table of personal records of students in a school. The Hong Kong ID Card number or a unique student number may be more appropriate.

2 Different key fields for different cases More to Learn Mobile telephone number can be used as a key field for membership of a boutique chain. The student number acts as a key field for a table of personal records of students at school.

3 Different key fields for different cases More to Learn Mobile telephone number can be used as a key field for membership of a boutique chain. The student number acts as a key field for a table of personal records of students at school.

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