HP 3000 Manuals HP 3000 Manuals
ITEM NAMES
All item names in a self-describing file must be unique unless all the
duplicate items are in data item equivalences. (Refer to the JOIN
command for more information on data item equivalences.)
Entries retrieved with a FIND have unique item names because they are
retrieved from a single data set. However, entries retrieved with a
MULTIFIND may have duplicate item names because they are retrieved from
more than one data set. The duplicate items must have been used in the
JOIN data item equivalence(s). An exception is made because the
duplicate items are of the same value although they may be of different
data types.
The first occurrence of the item in the compound data set entry is the
one recorded in the item description. Other occurrences are skipped
because the item has already been described. The data in the file
contains all occurrences of the data item even though the item
description appears only once. The offset reflects the first location in
the record where the data item value can be accessed.
Refer to example 2 for a self-describing file created from a MULTIFIND
where the JOIN item names are identical.
Examples
Example 1 - Single Data Set Retrieval
Given the following IMAGE data base:
BEGIN DATA BASE SD;
PASSWORDS:
ITEMS:
NAME, U10;
OCCUP, U16;
CITY, U10;
STATE, I2; << contains a numeric code for each state >>
SETS:
NAME: SET1, D;
ENTRY: NAME, OCCUP, CITY, STATE;
CAPACITY: 11;
END.
and the following FIND and SAVE commands:
>FIND STATE=2 OR STATE=3
USING SERIAL READ
4 ENTRIES QUALIFIED
>SAVE SAVEFILE
the SD file, SAVEFILE, appears as follows:
+----------------------------+
| labels 0-9 |
|----------------------------|
| item description label |
|----------------------------|
| global information label |
|----------------------------|
| |
| data |
| |
+----------------------------+
where the global information label contains:
(version) (length) (#items) (#labels) (#items/label) (size)
+----------------------------------------------------------------+
| A.00.00 | 38 | 4 | 2 | 8 | 15 |
+----------------------------------------------------------------+
and the item description label contains:
(name) (type) (offset) (length) (unused)
+-----------------+---------+----------+------------+-----------+
| NAME | 1 | 0 | 10 | 0 |
|-----------------|---------|----------|------------|-----------|
| OCCUP | 1 | 10 | 16 | 0 |
|-----------------|---------|----------|------------|-----------|
| CITY | 1 | 26 | 10 | 0 |
|-----------------|---------|----------|------------|-----------|
| STATE | 3 | 36 | 2 | 0 |
+-----------------+---------+----------+------------+-----------+
and the data in the file is (binary data is represented as periods):
_______________________________________________________________________
| |
| M FULLER ENGINEER CUPERTINO .. |
| H THOREAU ENGINEER SAN DIEGO .. |
| W EMERSON ENGINEER FT COLLINS.. |
| G SAND TECH WRITER CUPERTINO .. |
_______________________________________________________________________
Example 2 - Compound Data Set Retrieval
Given the following IMAGE data base:
BEGIN DATA BASE SD2;
PASSWORDS:
ITEMS:
NAME, U10;
OCCUP, U16;
CITY, U10;
STATE, I1;
NAME2, U10;
OCCUP2, U16;
CITY2, U10;
SETS:
NAME: SET1, D;
ENTRY: NAME, OCCUP, CITY, STATE;
CAPACITY: 11;
NAME: SET2, D;
ENTRY: NAME2, OCCUP2, CITY2, STATE;
CAPACITY: 11;
END.
and the following JOIN, MULTIFIND, and SAVE commands:
>JOIN SET1.STATE TO SET2.STATE
>MU STATE=2 OR STATE=3
USING SORT/MERGE
USING SERIAL READ
10 COMPOUND ENTRIES QULIFIED
>SAVE SAV2FILE
the SD file, SAV2FIL would look like this:
+----------------------------+
| labels 0-9 |
|----------------------------|
| item description label |
|----------------------------|
| global information label |
|----------------------------|
| |
| data |
| |
+----------------------------+
where the global information label contains:
(version) (length) (#items) (#labels) (#items/label) (size)
+-----------+--------+--------+---------+--------------+--------+
| A.00.00 | 74 | 7 | 2 | 8 | 15 |
+-----------+--------+--------+---------+--------------+--------+
and the item description label contains:
(name) (type) (offset) (length) (unused)
+-----------------+---------+---------+------------+----------+
| NAME | 1 | 0 | 10 | 0 |
|-----------------|---------|---------|------------|----------|
| OCCUP | 1 | 10 | 16 | 0 |
|-----------------|---------|---------|------------|----------|
| CITY | 1 | 26 | 10 | 0 |
|-----------------|---------|---------|------------|----------|
| STATE | 3 | 36 | 2 | 0 |
|-----------------|---------|---------|------------|----------|
| NAME2 | 1 | 38 | 10 | 0 |
|-----------------|---------|---------|------------|----------|
| OCCUP2 | 1 | 48 | 16 | |
|-----------------|---------|---------|------------|----------|
| CITY2 | 1 | 64 | 10 | 0 |
+-----------------+---------+---------+------------+----------+
and the data in the file is (binary data is represented as periods):
__________________________________________________________________________________
| |
| M FULLER ENGINEER CUPERTINO ..M FULLER2 ENGINEER CUPERTINO |
| M FULLER ENGINEER CUPERTINO ..H THOREAU2 ENGINEER CUPERTINO |
| M FULLER ENGINEER CUPERTINO ..G SAND2 TECH WRITER CUPERTINO |
| H THOREAU ENGINEER SAN DIEGO ..M FULLER2 ENGINEER CUPERTINO |
| H THOREAU ENGINEER SAN DIEGO ..H THOREAU ENGINEER CUPERTINO |
| H THOREAU ENGINEER SAN DIEGO ..G SAND2 TECH WRITER CUPERTINO |
| G SAND TECH WRITER CUPERTINO ..M FULLER2 ENGINEER CUPERTINO |
| G SAND TECH WRITER CUPERTINO ..H THOREAU2 ENGINEER CUPERTINO |
| G SAND TECH WRITER CUPERTINO ..G SAND2 TECH WRITER CUPERTINO |
| W EMERSON ENGINEER FT COLLINS..W EMERSON2 ENGINEER FT COLLINS|
__________________________________________________________________________________