Index Page ekappr_c

A B C D E F G H I J K L M N O P Q R S T U V W X

Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input | Detailed_Output Parameters Exceptions Files Particulars Examples | Restrictions Literature_References Author_and_Institution Version Index_Entries

#### Procedure

       void ekappr_c ( SpiceInt     handle,
                       SpiceInt     segno,
                       SpiceInt   * recno  )

#### Abstract

       Append a new, empty record at the end of a specified E-kernel
       segment.

#### Required_Reading

       EK

#### Keywords

       PRIVATE
       UTILITY

#### Brief_I/O

       Variable  I/O  Description
       --------  ---  --------------------------------------------------
       handle     I   File handle.
       segno      I   Segment number.
       recno      O   Number of appended record.

#### Detailed_Input

       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.

#### Detailed_Output

       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.

#### Parameters

       None.

#### Exceptions

       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.

#### Files

       See the EK Required Reading for a discussion of the EK file
       format.

#### Particulars

       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.

#### Examples

       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 );

#### Restrictions

       None.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman   (JPL)

#### Version

       -CSPICE Version 1.0.0, 09-JAN-2002 (NJB)

#### Index_Entries

       append record to EK segment

#### Link to routine ekappr_c source file ekappr_c.c

    Wed Apr  5 17:54:33 2017