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The set functions will be discussed in the next few sections using two single column tables: table x and table y. Before proceeding to the discussion on the set functions, let's first take a look at the contents of these tables. Table x: This document is created with the unregistered version of CHM2PDF Pilot Team Fly Page 76 NOTE Please be aware that the intersect set operator can introduce major performance problems. If you are venturing down this path, weigh the alternatives first. minus The minus set function returns all the rows in the first table minus the rows in the first table that are also in the second table.

The GUI can be used for performing day-to-day operations and can also be used as a great learning tool the first time you perform an operation. In many cases, you will be able to generate the low-level commands from the GUI and can copy them to a file to be used later on. As we've mentioned, there is a great deal that you will need to know in order to be able to provide well-rounded coverage of your Oracle environment. We can categorize the specialized areas of database management so that you will be aware of the whole picture and can break your work into well-defined groupings.

Among the attributes that can be defined when creating a sequence are a minimum value, a maximum value, a number to increment by and a number to start with. They are then made available to the systems applications and users that would need to generate them. For the following example, we have established a cust_id_seq sequence, which increments by one each time it's called. When we created the sequence, we specified that 104501 should be the number to start with. For demonstration purposes, we'll use the DUAL table to select the next two sequence numbers.