What I wanted to do here is, I wanted to show you, well, a very simple example of DDL statements. Here, for example, I'm going to do a create_table. I'm going to name the table customers. I'm going to say that I want a column custid in there of integer datatype. I'm going to say, that I'm going to place a column called custname; a variable length character to datatype, with 20 maximum characters in it. When I do a Control Enter, it will create that table. Now this filter over here, I've specified, only conclude tables that I have created. Here is the customers table. Notice that CUSTID and the CUSTNAME columns, that I constructed. This is the worksheet, here is the custid and the custname columns, and here it is, what it created, the CUSTID and CUSTNAME columns. CUSTID is the number, CUSTNAME is the VARCHAR2. That's how easy it is. That's a creation of a table. I can drop a table or remove it, by doing a drop table customers, which is also a DDL statement. When I refresh this, the table is now gone. Drop is delete. But I'm deleting an object, I'm not deleting a row in the table. I'm deleting the entire table. When you're deleting an entire object, such as a table, such as an index, you use the word drop. That's removing it. There's a create and drop. Well then you're going to say, well what about the other option which is alter? If I do a create table customers and I say, custid is a int data type. Custname is a variable length character to datatype. I create this table, and I do a refresh over here so I can see it. I can alter the table as well. When I look at this table structure right here, notice I've got custid and custname. I can do this. I can actually go in the command and I can say alter table. I specify the name of the table, customers, and I'm going to say I'm going to add a column called zipcode, that's going to be a variable length character two, with 10 characters. I run that command. Now when I click on ''Customers'', there's a ZIPCODE table, a table column added. That's the Alter Command. I showed you a Create Command that created the table structure as well, so that you saw the table structure being created. I added this column after the fact. There's create and alter. I also showed you drop, if I choose to write now, I can do a drop table customers like so. That will simply drop the customers table altogether. That is the create, alter, drop command. Those are DDL commands, that I gave you examples of.
