ANSI C, C++

#include <dctam.h>
int  dc_tam_delete (DCLONG tblid, struct DC_TAMKEY *keyadr,
                    int keyno, char *bufadr, int bufsize,
                    DCLONG flags)

K&R C

#include <dctam.h>
int       dc_tam_delete (tblid, keyadr, keyno, bufadr, bufsize,
                    flags)
DCLONG     tblid;
struct  DC_TAMKEY *keyadr;
int        keyno;
char       *bufadr;
int        bufsize;
DCLONG     flags;

The function dc_tam_delete() deletes a record indicated as a key value from a TAM table. The record to be deleted can be saved in the buffer. However, if the function dc_tam_delete() returns with an error, the buffer contents cannot be ensured.

If a TAM table is open under lock in records, lock in tables can be enabled with lock for update processing.

If the function dc_tam_delete() returns with an error, all the resources specified in this function are released, and the status before this function was called is regained. However, if an attempt is made to delete a TAM table which was acquired under lock for reference processing before this function was called, lock for update processing is enabled. (Lock for reference processing is not regained.)

Note the following when multiple records are specified for deletion:

• Even if one of the records causes an error, the processing of all the records specified in the function dc_tam_delete() results in an error, and the status before this function was called is regained.

tblid

Specify the table descriptor of the TAM table from which a record is deleted. This descriptor is the return value of the function dc_tam_open().

keyadr

Specify the address of the structure having the key value address of the record to be deleted. The structure format is as follows:

struct DC_TAMKEY {
                  char *keyname;
                  };

• keyname
  Specify the address of the key value. The key value must be specified with the length of the key area of the record to be deleted.
  

keyno

Specify the number of request records (number of structures specified for keyadr).

bufadr

If the record to be deleted is saved in the buffer, specify the buffer address. If DCTAM_NOOUTREC (the record to be deleted is not saved) is specified for flags, the specification for this argument is invalidated.

bufsize

If the record to be deleted is saved in the buffer, specify the length of the buffer. The return buffer length must be equal to or greater than (record length x number of request records). If DCTAM_NOOUTREC (the record to be deleted is not saved) is specified for flags, the specification for this argument is invalidated.

flags

Specify the following items in the format shown below:

• Record access type
• Lock release wait type
  

  {DCTAM_NOOUTREC|DCTAM_OUTREC}[|{DCTAM_WAIT|DCTAM_NOWAIT}]

• Flag 1
  Do not omit the specification of record access type. More than one access type cannot be specified at a time.
  

  DCTAM_NOOUTREC

  The record to be deleted is not saved.

  DCTAM_OUTREC

  The record to be deleted is saved.

• Flag 2
  If no lock release wait type is specified, the function does not wait for the resource to be released from lock and returns with an error. More than one lock release wait type cannot be specified at a time.
  

  DCTAM_WAIT

  The function waits for the resource to be released from lock.

  DCTAM_NOWAIT

  The function does not wait for the resource to be released from lock and returns with an error.

To delete all records stored in the hash format TAM table:

1. Save the key value of the record found by first retrieval as variable-1.
2. Using the key value of variable-1, execute a NEXT retrieval.
3. Save the key value of the record found in step 2 as variable-2.
4. Delete the key value record that was saved as variable-1.
5. Save the key value of variable-2 as variable-1.
6. Repeat steps 2 to 5 until step 2 encounters an error (NEXT retrieval).
7. After step 2 has encountered an error, delete the key value record that was last saved as variable-1.

Note that when you delete all records, performing the following steps may exert a high load on the CPU.

1. Execute a first retrieval of records.
2. Delete the record found in step 1.
3. Repeat step 1 and step 2 (that is, continue executing a first retrieval of records and deleting the record found).