Review Questions

1.	What are the three types of DML (Data Manipulation Language) statements?
2.	If the user SCOTT is granted the privilege to insert records on the OE.WAREHOUSES table using the command GRANT INSERT ON OE.WAREHOUSES WITH GRANT OPTION, what does the WITH GRANT OPTION clause allow SCOTT to do?
3.	Under which tiers of a three-tier Oracle environment does iSQL*Plus run?
4.	What two methods are used to rename a column in the report output of a SQL SELECT statement?
5.	ODBC provides what capability to client applications?
6.	Which SELECT statement keyword removes duplicate rows from the result of the query?
7.	What is the name of the set of library routines that allows a developer to send SQL statements from a C program?
8.	What are some of the differences between a DELETE and a TRUNCATE statement?
9.	The new MERGE statement combines the functionality of which two other DML statements?
10.	What function does the DESCRIBE command perform in SQL*Plus or iSQL*Plus?

Answers

1.	The three types of DML statements are INSERT, UPDATE, and DELETE.
2.	It allows SCOTT to grant another user, such as HR, the same INSERT privilege on the OE.WAREHOUSES table.
3.	iSQL*Plus runs on only the middleware tier where the Apache web server is running. However, Apache can run on the client with the user who is executing the SQL statements, on its own dedicated server, or on the same server as the Oracle database.
4.	You can rename a column in the report output by using the SQL*Plus or iSQL*Plus column command, or by specifying the alias name next to the column name in the SQL SELECT statement.
5.	ODBC (Open Database Connectivity) provides a client application that supports SQL commands and the capability to connect to a variety of different database servers without knowing the specific details as to how to connect and interact directly with the database.
6.	The DISTINCT keyword removes duplicate rows. If there is only one column in the result of a SQL query, there will be no duplicates of that column returned in the query result. If there are two columns in the result of the query, there will be one row returned for each unique combination of values in the first and the second column.
7.	The library routines for sending SQL statements from a C program are called the OCI (Oracle Call Interface).
8.	A DELETE statement may be rolled back, whereas a TRUNCATE is implicitly committed. The DELETE statement can conditionally specify which rows to delete, but a TRUNCATE statement removes the contents of the entire table. A DELETE statement retains the disk space in the table for future inserts or updates, but a TRUNCATE statement frees the disk space for other tables or database objects.
9.	MERGE combines the functionality of INSERT and UPDATE.
10.	The DESCRIBE command displays the structure of a table, including the column name, datatype, and whether the column is a required field.