HP 3000 Manuals HP 3000 Manuals
In Review Review the material in Lesson 5 by answering the following questions. ________________________________________________________________________ Q-1. What are three ways to select which data items to include in an IMAGE table? A-1. 1.`Get and order all items, then eliminate the unwanted ones. 2.`Get all items and pick which to include. 3.`Type in only the items and order you want. (Lesson 5:B) ________________________________________________________________________ Q-2. In the Item Clause of a view table, what are five ways to define a new item that will have a value different from any existing item's value? A-2. 1. Define the new item to be the result of a mathematical expression. 2. Extract a substring from an item by using the SUB function. 3. Substitute full words for a "coded" item by using a CASE statement. 4. Resolve a compound item by defining its parts as individual items. 5. Produce an average, standard deviation, sum, minimum, maximum, or count of a compound item's parts by using ROW functions. (Lesson 5:C, 5:D, and 5:F) ________________________________________________________________________ Q-3. What is the difference between a JOIN and a PRODUCTION operation in the Using Clause? A-3. A JOIN operation combines data from more than one table by matching records based on the value of a common item. Records which match on that item are combined into a single record in the resulting view table. A PRODUCTION operation does not specify an item on which to match records. It therefore generates a table with all possible combinations of all records specified from the source tables. (Lesson 5:C) ________________________________________________________________________ Q-4. Must the items specified in one JOIN operation have the same name? A-4. The item names need not be the same. However, the items must be of the same data type. (Lesson 5:E) In order for any records to be included in the table, the items specified must include an exact match on at least one value. ________________________________________________________________________ Q-5. Which records are included in the resulting view table when you don't enter anything in the Where Clause? A-5. All records in the table(s) specified in the Using Clause are included. (Lesson 5:C) ________________________________________________________________________ Q-6. How are records ordered when you list more than one item in the Sort Clause? A-6. First, records are grouped according to the value of the first item listed in the Sort Clause. Then the records within each grouping are ordered according to the value of the second item, and so on. (Lesson`5:D) ________________________________________________________________________