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(containing id_code keys) and <b>tims.k02</b> (containing author
keys).</p>
<p>One record type named <b>info</b> is declared to contain each of
the data fields. To accommodate the null byte that terminates
strings in C, each character field is one character longer than
specified in the requirements . Note that id_code is identified as
a unique key and that author is identified as a key. (Duplicate
keys are allowed unless the unique qualifier is present).</p>
<p>The schema is compiled with the following command:</p>
<pre>
<font color="#0000FF">ddlp tims.ddl</font>
</pre>
<p><font size="2">The <b>ddlp</b> will display the following
text:</font></p>
<pre>
<font color="#0000FF">db.* 1.0.0 Database Definition Language
Processor Utility Copyright (C) 2000 Centura Corporation, All Rights Reserved. 

Runtime dictionary memory requirements:   
   
   file table  :    876   
   record table:     12 
   field table :    120 
   set table   :      0 
   member table:      0
   sort table  :      0
   key table   :      0

   total       :   1008

0 errors detected</font>
</pre>
<p><font size="2">The <b>ddlp</b> reports the amount of dynamic
memory that will be allocated by the <b><i>db.*</i></b> runtime
system for the dictionary.</font></p>
<p>Upon successful completion, the <b>ddlp</b> will have created
two files. File <b>tims.dbd</b> contains the database dictionary.
File <b>tims.h</b> is the header file to be included in each C
source file using the tims database. The contents of <b>tims.h</b>
are shown below.</p>
<pre>
<font color="#0000FF">#ifndef TIMS_H
#define TIMS_H

/* <b><i>db.*</i></b> 1.0.0 */

/* Technical Information Management System*/    

/* database tims record/key structure declarations */

struct info {
   char  id_code[16];
   char  info_title[80];
   char  author[32];
   char  publisher[32];
   char  pub_date[12];
   int  info_type;
};

/* record, field and set table entry definitions */

/* File Id Constants */

/* Record Name Constants */
#define INFO 10000

/* Field Name Constants */
#define ID_CODE 0L
#define INFO_TITLE 1L
#define AUTHOR 2L
#define PUBLISHER 3L
#define PUB_DATE 4L
#define INFO_TYPE 5L

/* Set Name Constants */
/* Field Sizes */
#define SIZEOF_ID_CODE 16
#define SIZEOF_INFO_TITLE 80
#define SIZEOF_AUTHOR 32
#define SIZEOF_PUBLISHER 32
#define SIZEOF_PUB_DATE 12
#define SIZEOF_INFO_TYPE 2

#endif    /* TIMS_H */</font>
</pre>
<p><font size="2">This file contains a <b>struct</b> declaration
for the <b>info</b> record. This <b>struct</b> is for use by the
C/C++ application in declaring variables that contain occurrences
of the <b>info</b> record from the database. Also included in this
file are constant definitions for the <b>info</b> record and for
each data field. These constants will be passed to the
<b><i>db.*</i></b> C functions that require them.</font></p>
<p>The next step is to initialize the database with the following
command:</p>
<pre>
<font color="#0000FF">initdb tims</font>
</pre>
<p><font size="2">Then <b><i>db.*</i></b> will display the
following text and, except in the very first initialization, prompt
you for confirmation:</font></p>
<pre>
<font color="#0000FF">Database Initialization Utility  db.* 1.0.0
Copyright (C) 2000 Centura Corporation, All Rights Reserved

Initialization of database: tims

WARNING: this will destroy contents of the following files:

   tims.d01
   tims.k01
   tims.k02

continue? (y/n)
</font>
</pre>
<p><font size="2">A "y" (yes) response will complete the
initialization of the database files; the listed files will be
overwritten.</font></p>
<h3><a name="ProgramDesign" id="ProgramDesign"></a>3.4.3 Program
Design</h3>
<p><font size="2">The program for this example consists of the
following functions:</font></p>
<table cellspacing="0" border="0" cellpadding="7" width="542">
<tr>
<td width="18%" valign="top">
<p><b><font size="2">main</font></b></p>
</td>
<td width="82%" valign="top">
<p><font size="2">Main program, command menu control</font></p>
</td>
</tr>
<tr>
<td width="18%" valign="top">
<p><b><font size="2">ent_info</font></b></p>
</td>
<td width="82%" valign="top">
<p><font size="2">Enter technical information data</font></p>
</td>
</tr>
<tr>
<td width="18%" valign="top">
<p><b><font size="2">del_info</font></b></p>
</td>
<td width="82%" valign="top">
<p><font size="2">Delete technical information data</font></p>
</td>
</tr>
<tr>
<td width="18%" valign="top">
<p><b><font size="2">by_id</font></b></p>
</td>
<td width="82%" valign="top">
<p><font size="2">Find technical information by
<b>id_code</b></font></p>
</td>
</tr>
<tr>
<td width="18%" valign="top">
<p><b><font size="2">by_author</font></b></p>
</td>
<td width="82%" valign="top">
<p><font size="2">Find technical information by author</font></p>
</td>
</tr>
<tr>
<td width="18%" valign="top">
<p><b><font size="2">get_info</font></b></p>
</td>
<td width="82%" valign="top">
<p><font size="2">Get technical information data from
user</font></p>
</td>
</tr>
<tr>
<td width="18%" valign="top">
<p><b><font size="2">pr_info</font></b></p>
</td>
<td width="82%" valign="top">
<p><font size="2">Print technical information data</font></p>
</td>
</tr>
</table>
<p><font size="2">Figure 3-3 shows the function call structure for
the program.</font></p>
<p align="center">&nbsp;</p>
<p align="center"><b><font size="2"><img alt=
"dbstar_3-3.gif - 2237 Bytes" border="0" height="151" src=
"dbstar_3-3.gif" width="307"></font></b></p>
<p align="center">Fig. 3-3. Call Structure of the Example
Program</p>
<p>The <b><i>db.*</i></b> runtime library functions to be used in
the example are summarized in the following table. Note that, by
convention, all <b><i>db.*</i></b> runtime functions begin with a
<b>d_</b> prefix.</p>
<table cellspacing="0" border="0" cellpadding="7" width="535">
<tr>
<td width="24%" valign="top">
<p><b><font face="Palatino,Book Antiqua" size=
"2">d_lockcomm</font></b></p>
</td>
<td width="76%" valign="top">
<p><font face="Palatino,Book Antiqua" size="2">Select a lock
manager communication protocol</font></p>
</td>
</tr>
<tr>
<td width="24%" valign="top">
<p><b><font face="Palatino,Book Antiqua" size=
"2">d_open</font></b></p>
</td>
<td width="76%" valign="top">
<p><font face="Palatino,Book Antiqua" size="2">Open a
database</font></p>
</td>
</tr>
<tr>
<td width="24%" valign="top">
<p><b><font face="Palatino,Book Antiqua" size=
"2">d_close</font></b></p>
</td>
<td width="76%" valign="top">
<p><font face="Palatino,Book Antiqua" size="2">Close a
database</font></p>
</td>
</tr>
<tr>
<td width="24%" valign="top">
<p><b><font face="Palatino,Book Antiqua" size=
"2">d_fillnew</font></b></p>
</td>
<td width="76%" valign="top">
<p><font face="Palatino,Book Antiqua" size="2">Fill and store a new
record occurrence</font></p>
</td>
</tr>
<tr>
<td width="24%" valign="top">
<p><b><font face="Palatino,Book Antiqua" size=
"2">d_keyfind</font></b></p>
</td>
<td width="76%" valign="top">
<p><font face="Palatino,Book Antiqua" size="2">Find a key
occurrence</font></p>
</td>
</tr>
<tr>
<td width="24%" valign="top">
<p><b><font face="Palatino,Book Antiqua" size=
"2">d_keynext</font></b></p>
</td>
<td width="76%" valign="top">
<p><font face="Palatino,Book Antiqua" size="2">Find the next key
occurrence</font></p>
</td>
</tr>
<tr>
<td width="24%" valign="top">
<p><b><font face="Palatino,Book Antiqua" size=
"2">d_keyread</font></b></p>
</td>
<td width="76%" valign="top">
<p><font face="Palatino,Book Antiqua" size="2">Read value of last
found key</font></p>
</td>
</tr>
<tr>
<td width="24%" valign="top">
<p><b><font face="Palatino,Book Antiqua" size=
"2">d_recread</font></b></p>
</td>
<td width="76%" valign="top">
<p><font face="Palatino,Book Antiqua" size="2">Read a record
contents</font></p>
</td>
</tr>
<tr>
<td width="24%" valign="top">
<p><b><font face="Palatino,Book Antiqua" size=
"2">d_delete</font></b></p>
</td>
<td width="76%" valign="top">
<p><font face="Palatino,Book Antiqua" size="2">Delete a record
occurrence</font></p>
</td>
</tr>
</table>
<h3><a name="Description" id="Description"></a>3.4.4 Program
Description</h3>
<p><font size="2">The C code for the main program is given below.
The first four lines include directives to incorporate the standard
C header file <b>stdio.h</b>, the standard <b><i>db.*</i></b>
header file <b>db.star.h</b>, and the <b>tims</b> database header
file <b>tims.h</b>. The <b><i>db.*</i></b> header file contains the
constant definitions for the <b><i>db.*</i></b> function return
status code. The definition of LOCKCOMM_DATA needs to be done
before <b>db.star.h</b> is included in one module in your
application.</font></p>
<p>A variable called <b>irec</b> is a globally declared <b>info</b>
structure (declared in <b>tims.h</b>) to be used by all of the
functions for storing <b>info</b> record data.</p>
<pre>
<font color="#0000FF">#include &lt;stdio.h&gt;
#define LOCKCOMM_DATA
#include "db.star.h"
#include "tims.h"
DB_TASK *Currtask;

struct info irec;   

/* Technical Information Management System */
main()
{
   char cmd[20];  /* command entry string */
   int err;

/* open the "tims" database */
   if ((err=d_opentask(&amp;Currtask)) != S_OKAY ||
       (err=d_open("tims","o", Currtask)) != S_OKAY) 
   {
      printf("Failure to open database, error=%d\n", err);
      return (0);
   }

   for ( ; ; )
   {
      /* display command menu */
      printf("\nTIMS Commands:\n");
      printf("   1 - Enter technical information\n");
      printf("   2 - Delete technical information\n");
      printf("   3 - Find technical info by id_code\n");
      printf("   4 - Find technical info by author\n");
      printf("   q - Quit\n");
      printf("enter command: ");
      gets(cmd);
      switch (cmd[0]) 
      {
         case '1':    ent_info();   break;
         case '2':    del_info();   break;
         case '3':    by_id();      break;
         case '4':    by_author();   break;
         case 'q':    d_close(Currtask);   exit(0);
         default :
             printf("*** bad command--re-enter\n");
            break;
      }
   }
}
</font>
</pre>
<p><font size="2">In this example we are opening the database in
single user mode, so we are using no lock manager. For a full
explanation of the various lock manager communication options and
issues, see the <b><i>db.*</i></b> <i>Multi-User
Guide</i>.</font></p>
<p>The <b>d_opentask</b> call requires one parameter, a pointer to
the task pointer. <b>db.*</b> will allocate a task structure and
return the pointer to the program for use in all subsequent calls
that are associated with the task. The <b>d_open</b> call requires
three arguments. The first argument is the name of the database to
be opened. The second argument (<b>o</b>) indicates that the
database is to be opened in one user mode (that is, only one user
will access the database, and the lock manager is not required). In