HP 3000 Manuals HP 3000 Manuals
Lesson 3: Quiz 1
1. Name the three ways in which you can manipulate tables in BRW.
Join, Open Join, and Merge.
2. If you join two or more tables with the common item ORDER-NO, when
is record written to the result table?
A record is written to the result table whenever an
identical value for ORDER-NO appears in every table.
3. What happens if you do not define a relation when joining tables?
BRWjoins each record of one table with each record in the
others. (A Cartesian product.) For example, if you have
1,000,000 records in one table and 500,000 in another, your
result table would contain 500,000,000,000 records.
4. What is the effect of defining the following relation condition?
MONTH_OF (SHIPMENT-DATE) = 12
A record will only be written to the result table if
SHIPMENT-DATE is December (12th month).
5. How can you make sure that an item that is present in a data set
is not available for use in a report?
By excluding the item from projection on the Project Items
screen. Only items projected from a table (that is, with a
X in the Project field) can be used in a report.
6. Is QUANTITY = 0 the same as QUANTITY = NO_VALUE? If not, why not?
No. QUANTITY = 0 means that a value for item QUANTITY
exists, and that value is 0. QUANTITY = NO_VALUE means
that a there is no value for item QUANTITY, that is, a
value for QUANTITY does not exist.