1. Answer to the questions using the following table (20 points) PROJ NUM | PROJ
ID: 3752660 • Letter: 1
Question
1. Answer to the questions using the following table (20 points) PROJ NUM | PROJ NAME EMP NUM EMP NAME | JOB CODE JOB CHG HOURI PROJ HOURS EMP PHONE 1 Hurricane 1 Hurricane 1 Hurricane 2 Coast 2 Coast 3 Satellite 3 Satellite 3 Satelite 3 Satellite 101 John D. Newson EE 105 David F. Schwann CT 10 Anne R. Ramoras CT 101 John D. Newson EE 108 June H. Sattlemeir EE 110 Anne R. Ramoras CT 105 David F. Schwann CT 123 112 Allecia R. SmithBE 85.00 60.00 60.00 85.00 85.00 62.00 26.00 85.00 85.00 13.3 653-234-3245 16.2 653-234-1123 14.3 615-233-5568 19.8 653-234-3254 17.5 905-554-7812 11.6 615-233-5568 23.4 653-234-1123 19.1 615-233-5432 20.7 615-678-6879 D. Chen (1) What is the identifier in the above table? Justify your answer based on the definition of the identifier. (5 points) (2) What is insertion anomaly? How is it related with the identifier? (5 points) (3) How can you describe the insertion anomaly in the above table using the identifier you have found in (1)? Use some specific examples or business scenarios. (10 points)Explanation / Answer
An identifier in a database is a key that uniquely identifies a row in a table. In the given table PROJ_NUM and EMP_NUM when combined together, uniquely identifies a row in a table. Insertion anomaly is the inability of a database to add a new record to an existing database due to the absence of the other database. In the given database if we want to add a new employee detail in the table we won’t be able to add unless we have project detail also. Here both PROJ_NUM and EMP_NUM are combined identifier of the table hence one record cannot be added in the absence of other value. Insertion anomaly exist in the given table because the identifier in the given table is combined i.e. PROJ_NUM and EMP_NUM both when combined uniquely identifies a row in the table. In the absence of any of these values a new record cannot be inserted in the table.
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