Practice exercise

1. Which of the following features are not available in SQL Developer?

   1. Query builder

   2. Database export and import

   3. Database backup and recovery functions

   4. Code Subversion repository

2. For a function to be called from the SQL expression, which of the following conditions should it obey:

   1. A function in the SELECT statement should not contain DML statements.

   2. The function should return a value.

   3. A function in the UPDATE or DELETE statement should not query the same table.

   4. A function called from SQL expressions cannot contain the TCL (COMMIT or ROLLBACK) command or the DDL (CREATE or ALTER) command.

3. The following query is executed in the ORADEV schema:

     SELECT NAME, referenced_owner, referenced_name 
     FROM all_dependencies
     WHERE owner = USER
     AND referenced_type IN ('TABLE', 'VIEW')
     AND referenced_owner IN ('SYS')
     ORDER BY owner, NAME, referenced_owner, referenced_name;

   Which statement is true about the output of this query?

   1. It displays the schema objects created by the user ORADEV which use a table or view owned by SYS.

   2. Exception occurs as user ORADEV has insufficient privileges to access ALL_DEPENDENCIES view.

   3. It displays all PL/SQL code objects that reference a table or view directly for all the users in the database.

   4. It displays only those PL/SQL code objects created by the user OE that reference a table or view created by the user SYS.

4. Which of the following is true about PL/SQL blocks?

   1. Exception is a mandatory section without which an anonymous PL/SQL block fails to compile.

   2. Bind variables cannot be referred inside a PL/SQL block.

   3. The scope and visibility of the variables declared in the declarative section of the block is within the current block only.

   4. The RAISE_APPLICATION_ERROR procedure maps a predefined error message to a customized error code.

5. From the following options, identify the ways of defining exceptions:

   1. Declare a EXCEPTION variable and raise it using the RAISE statement.

   2. Use PRAGMA EXCEPTION_INIT to associate a customized exception message to a pre-defined Oracle error number.

   3. Declare a EXCEPTION variable and use it in RAISE_APPLICATION_ERROR.

   4. Use RAISE_APPLICATION_ERROR to create a dynamic exception at any stage within the executable or exception section of a PL/SQL block.

6. Chose the differences between procedures and functions:

   1. A function must mandatorily return a value, while a procedure may or may not.

   2. A function can be called from SQL queries, while a procedure can never be invoked from SQL.

   3. A function can accept parameters passed by value, while a procedure can accept parameters as passed by reference only.

   4. A standalone function can be overloaded but a procedure cannot.

7. Examine the values of the cursor attribute for the following query and pick the attribute with the wrong value:

     BEGIN
     …
     SELECT ENAME, SAL
     INTO L_ENAME, L_SAL
     FROM EMPLOYEES
     WHERE EMPID = 7900;
     …
     END;

   1. SQL%ROWCOUNT = 1

   2. SQL%ISOPEN = FALSE

   3. SQL%FOUND = FALSE

   4. SQL%NOTFOUND = FALSE