CHAPTER 3
Hands-On Assignments
1. Create a new table containing the category code and description for the categories of books sold by JustLee Books. The table should be called CATEGORY, and the columns should be CatCode and CatDesc. The CatCode column should store a maximum of 2 characters, and the CatDesc column should store a maximum of 10 characters. create table category
(CatCode varchar2(2), CatDesc varchar2(10));,
2. Create a new table containing these four columns: Emp#, Lastname, Firstname, and Job_class. The table name should be EMPLOYEES. The Job_class column should be able to store character strings up to a maximum length of four, but the column values shouldn’t be padded if the value has less than four characters. The Emp# column contains a numeric ID and should allow a five-digit number. Use column sizes you consider suitable for the Firstname and Lastname columns. create table EMPLOYEES
(Emp# number(5,0), Lastname varchar2(12), Firstname varchar2(12), Job_Class char(4));
3. Add two columns to the EMPLOYEES table. One column, named EmpDate, contains the date of employment for each employee, and its default value should be the system date. The second column, named EndDate, contains employees’ date of termination.
Alter Table EMPLOYEES
Add (Empdate Date Default System, EndDate Date);
4. Modify the Job_class column of the EMPLOYEES table so that it allows storing a maximum width of two characters.
Alter Table EMPLOYEES modify (Job_Class char(2));
5. Delete the EndDate column from the EMPLOYEES table.
Alter Table EMPLOYEES drop column EndDate;
6. Rename the EMPLOYEES table as JL_EMPS.
Rename Employees To JL_EMPS;
7. Create a new table containing these four columns from the existing BOOKS table: ISBN, Cost, Retail, and Category. The name of the ISBN column should be ID, and the other col- umns should keep their original names.