Answer to Question #224757 in Databases | SQL | Oracle | MS Access for Sadaf

Question

Suppose we have 999 records of employees Emp1, Emp2, Emp5, Emp6 and so on up to Emp998 and Emp999 stored in a sequence. Hence, records are nothing but a row in the table. In the employee table, we want to insert new records Emp3 and Emp4 in the sequence, and once we have done insertion we need to update and retrieve the record efficiently to optimize the performance of a database by minimizing the access time when query is being executed.

You are required to solve the problem with the index sequential access method with pros and cons in the given scenario.

Answer 1

INSERT INTO Employee (empId)
VALUES ("Emp3");
INSERT INTO Employee (empId)
VALUES ("Emp4");

One advantage of using Index sequential access method (ISAM) is that it provides flexibility of making any column a primary key and an index is generated on that column.

Also this method of accessing records in the database is easy and quick.

The disadvantage of ISAM is that maintaining index requires cost to be incurred.