HP Integrity NonStop J-Series - Manual (Page 165)

USING AN ENABLE APPLICATION
Reading Records
READING RECORDS
You can read a record in a data base file by requesting several
different types of read operations. These operations are:
• READ FIRST
• READ NEXT
• READ APPROXIMATE
• READ EXACT
• READ GENERIC
You can request these operations by using function keys F4, F5,
F6, F7, and F8.
When you request a read operation, you select a key field with
which the application performs the operation. You select this
key field by positioning the cursor within the field. If a
particular record has only one key, the application assumes that
you have selected that key regardless of where you position the
cursor.
If you do not position the cursor within a key field, the
application assumes that you have selected the first key field
that appears on the screen. For this reason, this key field is
sometimes called the default key.
If an application displays several boxes, you must position the
cursor within the desired box before you request a read
operation.
READ FIRST (F4)
When you want to retrieve the first record (or records) in the
file according to a selected key field, request a READ FIRST
operation. If you select a primary key field, you retrieve the
first record actually stored in the file. If you select an
alternate key field, you retrieve the first record in the file
sorted by the alternate key field. Both primary and alternate
keys are sorted in ascending sequence.
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