Introduction to Database Management Systems by Kahate Atul

Author:Kahate, Atul...
Language: eng
Format: epub
Published: 2014-05-21T23:17:03.374000+00:00

Fig. 6.19 Granting selective UPDATE privileges

The names of the columns for which the user should have update privilege appear inside the bracket after the table name.

For example, let us assume that the Sales table contains four columns, namely Salesperson_ID, Customer_ID, Sale_Date and Sale_Amount. Let us assume that Ana is a sales officer, who must not be able to update the sales amount. She should be allowed to update the values in the three other columns. In such a case, Prashant can issue the following GRANT statement:

GRANT UPDATE ON Sales (Salesperson_ID, Customer_ID, Sale_Date) TO Ana;

Now, Ana can update the ID of the salesperson, the ID of the customer and the date on which the sale happened in the Sales table. However, she cannot update the values in the amount field. Of course, Prashant can allow the UPDATE privilege on only one column (rather than on multiple columns) to any user. For example, Prashant can allow Radhika to update just the date on which the sale happened:

GRANT UPDATE ON Sales (Sale_Date) TO Radhika;

REFERENCES privilege is similar in concept to UPDATE privilege. The idea behind REFERENCES privilege can be summarised thus:

When user A grants the REFERENCES privilege to user B, user B can create a foreign key reference on a table owned by A.

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