void ekappr_c ( SpiceInt handle,
SpiceInt segno,
SpiceInt * recno )
Append a new, empty record at the end of a specified E-kernel
segment.
EK
PRIVATE
UTILITY
Variable I/O Description
-------- --- --------------------------------------------------
handle I File handle.
segno I Segment number.
recno O Number of appended record.
handle is a file handle of an EK open for write access.
segno is the number of the segment to which the record
is to be added. EK segment numbers range from
zero to N-1, where N is the number of segments
in the kernel.
recno is the number of the record appended by this
routine. recno is used to identify the record
when writing column entries to it. EK record
numbers range from 0 to N-1, where N is the
number of records in the segment containing
the record.
None.
1) If handle is invalid, the error will be diagnosed by routines
called by this routine. The file will not be modified.
2) If segno is out of range, the error SPICE(INVALIDINDEX)
will be signalled. The file will not be modified.
3) If an I/O error occurs while reading or writing the indicated
file, the error will be diagnosed by routines called by this
routine. The file may be corrupted.
See the EK Required Reading for a discussion of the EK file
format.
This routine operates by side effects: It appends a new, empty
record structure to an EK segment. The ordinal position of the
new record is one greater than the previous number of records in
in the segment.
After a new record has been appended to a segment by this routine,
the record must be populated with data using the ekace*_c
routines. EKs are valid only when all of their column entries
are initialized.
To insert a record into a segment at a specified ordinal position,
use the routine ekappr_c.
This routine cannot be used with the "fast write" suite of
routines. See the EK Required Reading for a discussion of the
fast writers.
1) Append a record to a specified segment.
Suppose we have an E-kernel named order_db.ek which contains
records of orders for data products. The E-kernel has a
table called DATAORDERS that consists of the set of columns
listed below:
DATAORDERS
Column Name Data Type
----------- ---------
ORDER_ID INTEGER
CUSTOMER_ID INTEGER
LAST_NAME CHARACTER*(*)
FIRST_NAME CHARACTER*(*)
ORDER_DATE TIME
COST DOUBLE PRECISION
The order database also has a table of items that have been
ordered. The columns of this table are shown below:
DATAITEMS
Column Name Data Type
----------- ---------
ITEM_ID INTEGER
ORDER_ID INTEGER
ITEM_NAME CHARACTER*(*)
DESCRIPTION CHARACTER*(*)
PRICE DOUBLE PRECISION
We'll suppose that the file order_db.ek contains two segments,
the first containing the DATAORDERS table and the second
containing the DATAITEMS table.
If we wanted to insert a new record into the DATAORDERS
table in position 0, we'd make the following calls:
#include "SpiceUsr.h"
.
.
.
/.
Open the database for write access. This call is
made when the file already exists. See ekopn_c for
an example of creating a new file.
./
ekopw_c ( "order_db.ek", &handle );
/.
Append a new, empty record to the DATAORDERS
table. Recall that the DATAORDERS table
is in segment number 0. The call will return
the number of the new, empty record.
./
ekappr_c ( handle, 0, &recno );
/.
At this point, the new record is empty. A valid EK
cannot contain empty records. We fill in the data
here. Data items are filled in one column at a time.
The order in which the columns are filled in is not
important. We use the ekace*_c (add column entry)
routines to fill in column entries. We'll assume
that no entries are null. All entries are scalar,
so the entry size is 1.
./
isnull = SPICEFALSE;
size = 1;
/.
The following variables will contain the data for
the new record.
./
ordid = 10011;
custid = 531;
lname = "scientist";
fname = "joe";
odate = "1995-sep-20";
cost = 5000.;
/.
Note that the names of the routines called
correspond to the data types of the columns: the
last letter of the routine name is C, I, or D,
depending on the data type. Time values are
converted to ET for storage.
./
ekacei_c ( handle, segno, recno, "order_id",
size, ordid, isnull );
ekacei_c ( handle, segno, recno, "customer_id",
size, custid, isnull );
ekacec_c ( handle, segno, recno, "last_name",
size, vallen, lname, isnull );
ekacec_c ( handle, segno, recno, "first_name",
size, vallen, fname, isnull );
utc2et_c ( odate, &et );
ekaced_c ( handle, segno, recno, "order_date",
size, et, isnull );
ekaced_c ( handle, segno, recno, "cost",
size, cost, isnull );
/.
Close the file to make the update permanent.
./
ekcls_c ( handle );
None.
None.
N.J. Bachman (JPL)
-CSPICE Version 1.0.0, 09-JAN-2002 (NJB)
append record to EK segment
Link to routine ekappr_c source file ekappr_c.c
|