Volume Number: 14 (1998)
Issue Number: 4
Column Tag: Rhapsody

OpenBase

by Gene Backlin

A Solid Database Framework for Rhapsody

OpenBase is a solid database framework which will address your data handling requirements for Rhapsody. Like Rhapsody, OpenBase's foundation is with NeXTSTEP. It has evolved through the years to provide a mature environment for stand alone users as well as over distributed networks. For the developer, OpenBase has a rich set of application APIs that incorporate the C and Objective-C languages. Regardless of developers programming background Mac OS or NeXTSTEP/OpenStep, the OpenBase API framework allows quick development of full scale database applications.

This article will illustrate:

• Steps to build SimpleTool, an application that queries a "Movie" database, show just how simple is writing an OpenBase database application.
• Help Desk, an application using OpenBaseAdvancedAPI to address multi-tiered database interaction over local area networks.
• OpenBase Manager, OpenBase's data management and interactive tool.

SimpleTool demonstrates interaction with a relational database interaction without using the tedious programming overhead common with databases. Using C or Objective-C is the simplest way to access OpenBase. SimpleTool will retrieve from the database the movies and the revenue from the producing studios. Listing 1 illustrates the OpenBase API framework. A discussion follows.

Listing 1: SimpleTool_main.m

#import <Foundation/Foundation.h>
#import <OpenBaseAPI/OpenBase.h>

int main (int argc, const char *argv[])
{
  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  int returnCode;
  OpenBase *connection = ob_newConnection();

  //variables to hold values
  char movieTitle[256];
  char studioName[256];
  long revenue;

  if (!ob_connectToDatabase
    (connection, "Movie", "*", "", "", &returnCode))
    {
    printf("%s\n", ob_connectErrorMessage(connection));
    return -1;
    }

  ob_makeCommand(connection,"select t0.TITLE, t0.REVENUE, 
    t1.NAME from MOVIE t0, STUDIO t1 where 
    t0.STUDIO_ID = t1.STUDIO_ID order by t0.REVENUE DESC");

  if (!ob_executeCommand(connection))
    {
    printf("ERROR - %s\n",ob_serverMessage(connection));
    ob_invalidate(connection);
    return -1;
    }

  ob_bindString(connection, movieTitle);
  ob_bindLong(connection, &revenue);
  ob_bindString(connection, studioName);

  while (ob_nextRow(connection)) 
    {
    printf("%s made $%ld for %s.\n",movieTitle, revenue, 
      studioName);
    }

  ob_invalidate(connection);
  [pool release];
  exit(0);
  return 0;
}

Main begins by establishing a connection to the database, if a connection was not made, print the offending message returned from the connection object and exit. Using the ob_connectToDatabase() function, establish a connection to the database with the database name, hostname, logon id and password. Note the argument "*". The database connection is made directly to the local machine on a standalone computer, but will poll all hosts on a local area network. This is an example of OpenBase's scaleability.

  int returnCode;
  OpenBase *connection = ob_newConnection();
  // ...
  if (!ob_connectToDatabase(connection, "Movie", "*", "", "", 
    &returnCode))
    {
    printf("%s\n", ob_connectErrorMessage(connection));
    return -1;
    }

After a successful connection has been established, the ob_makeCommand() function is used to send SQL statements. The TITLE and REVENUE data columns from the MOVIE table as well as the associated studio NAME from the STUDIO table are retrieved. The SQL statements are now buffered for later execution by the database server.

  ob_makeCommand(connection,"select t0.TITLE, t0.REVENUE,
  t1.NAME from MOVIE t0, STUDIO t1 where t0.STUDIO_ID =
  t1.STUDIO_ID order by t0.REVENUE DESC");

The ob_executeCommand() passes the buffered SQL statements to the database server and returns TRUE for successful and FALSE for failed execution.

  if (!ob_executeCommand(connection))
    {
    printf("ERROR - %s\n",ob_serverMessage(connection));
    ob_invalidate(connection);
    return -1;
    }

The ob_bindString() and ob_bindLong() functions, bind the resulting data columns from the database, to the receiving program variables. SimpleTool binds the variables movieTitle, revenue and studioName respective to the order of the initial SELECT statement.

  ob_bindString(connection, movieTitle);
  ob_bindLong(connection, &revenue);
  ob_bindString(connection, studioName);

ob_nextRow() increments through the result rows and retrieves the data. FALSE is returned when all data is processed.

  while (ob_nextRow(connection)) 
    {
    printf("%s made $%ld for %s.\n",movieTitle, revenue, 
      studioName);
    }

Main ends with a call to terminate the connection to the database server.

  ob_invalidate(connection);

Help Desk, addresses multi-tiered database requirements by directly connecting to the user interface through the OpenBaseAdvancedAPI as seen in Figure 1.

Figure 1. Help Desk Manager.

Designing the Interface

The Apple supplied tool Interface Builder is used to design the user interface. Information on Interface Builder is detailed at http://devworld.apple.com/techinfo/techdocs/rhapsody/apple.com. See Figure 2 for a screen shot of a connection being performed using Interface Builder.

Figure 2. Making the Interface Builder Object Connection.

Managing the Interface and Database Relationships

Two FormManagers and one ReadTableManager are created. The first FormManager lists customer questions and the other displays who asked the question. The ReadTableManager manages a picklist of information.

  tableManager = [[ReadTableManager alloc] init];
  formManager = [[FormManager alloc] init];
  contactsFormManager = [[FormManager alloc] init];

To set the key attribute and table, each object must be initialized.

  [tableManager setKeyAttribute:@"support._rowid"];
  [tableManager setTableName:@"support"];

  [formManager setKeyAttribute:@"support._rowid"];
  [formManager setTableName:@"support"];

  [contactsFormManager setKeyAttribute:@"contacts._rowid"];
  [contactsFormManager setTableName:@"contacts"];

Connect the interface objects; tableManager, formManager and contactsFormManager to the database.

  [tableManager setConnection:connection];
  [formManager setConnection:connection];
  [contactsFormManager setConnection:connection];

Set specific query ordering. In this example "ASC" is ascending.

  [tableManager setOrderBy:@" ORDER BY
    support.shortQuestion ASC"];

Bind the screen objects to the database columns.

#define FIELD(outlet) [OutletManager newForOutlet:outlet]
#define TEXT(outlet) [OutletTextManager newForOutlet:outlet]
#define POPUP(outlet) [OutletPopUpManager   \
                      newForOutlet:outlet]

[formManager addOutlet:FIELD(shortQuestion) 
      withColumnName:@"support.shortQuestion"];
[formManager addOutlet:FIELD(product) 
      withColumnName:@"support.product"];
[formManager addOutlet:TEXT(textQuestion) 
      withColumnName:@"support.question"];
[formManager addOutlet:TEXT(textAnswer) 
      withColumnName:@"support.answer"];
[formManager addOutlet:FIELD(dateCreated) 
      withColumnName:@"support.dateCreated"];
[formManager addOutlet:POPUP(answered) 
      withColumnName:@"support.answered"];

Set up the Contacts Form to be a target of the FormManager.

[contactsFormManager addOutlet:FIELD(firstname) 
      withColumnName:@"contacts.firstname"];
[contactsFormManager addOutlet:FIELD(lastname) 
      withColumnName:@"contacts.lastname"];
[contactsFormManager addOutlet:FIELD(email) 
      withColumnName:@"contacts.email"];

Add each column to initialize the table.

[tableManager addColumn:@"support.product" 
    title:@"Product"];
[tableManager addColumn:@"support.answered" 
    title:@"Answered"];
[tableManager addColumn:@"support.shortQuestion" 
    title:@"Summary"];

Initialize the windowTableView object, to display the query results.

[tableManager setTableView:windowTableView];

Establishing Database Relationships

The formManager will display related details when a selection is made in the tableManager. To accomplish this, a target relationship must be made between the tableManager and formManager.

[tableManager addTarget:formManager
    withValue:@"support._rowid"];

The contactsFormManager displays the contacts through the contacts_id key.

[formManager addOutlet:contactsFormManager
    withColumnName:@"support.contacts_id"];

The formManager sets the SQL "WHERE" constraints as well as subqueries.

[tableManager fetchData:[formManager whereConstraints]];

Insulation from Direct SQL

OpenBase's OpenBaseAdvancedAPI, completely insulates you from SQL commands like SEARCH, RESET, SAVE and DELETE, by the following methods.

- (void)findAction:sender
{
  [tableManager fetchData:[formManager whereConstraints]];
}

- (void)resetAction:sender
{
  [tableManager resetAction:self];
}

- (void)saveAction:sender
{
  [formManager saveChanges];
}

- (void)deleteAction:sender
{
  [tableManager deleteAction:self];
}

In addition to the developer API frameworks, OpenBase like Rhapsody, designed graphical tools to simplify tasks. OpenBase Manager simplifies the following:

• Managing Database servers across local area networks
• Viewing Databases
• Editing Database schemas
• Managing Database security

OpenBase Interactive Database Toolset

The following screen shots display OpenBase's rich set of tools.

Figure 3. OpenBase Database Manager.

Figure 4. User Administration.

Figure 5. Permission Administration.

Figure 6. Database Table Administration.

Sirius Connections, a leading provider of internet services for the San Francisco area, uses OpenBase for billing and maintaining historical records on 15,000 customers. "Our whole operation is built on OpenBase technology, " says Andreas Glocker, CEO of Sirius Connections, "Automating our business on OpenBase has made all the difference. It has given us the competitive advantage."

"One of our programmers wrote a system using the OpenBase API in less than a day. Doing the same thing using Oracle OCI's took more than three," says Kevin Ford, President of ComputerActive located in Ontario Canada, "OpenBase demonstrates a level of quality and robustness rarely seen in the software world."

Robert L. Peek, founder of the Peek Financial Group, says, "We have adopted OpenBase as an enterprise wide solution for our firm. We have found it to be an industrial strength database with excellent support."

OpenBase supports ODBC for Mac OS and Windows and has a native JDBC driver. For further information about OpenBase and how you can get a FREE single-user runtime, you can contact:

OpenBase International, Ltd
58 Greenfield Road
Francestown, NH 03043
Tel: 603-547-8404 -- Fax: 603-547-2423
e-mail: info@openbase.com
internet: http://www.openbase.com

Gene Backlin, gbacklin@MariZack.com, has been programming since 1978, and is owner and principal consultant of MariZack Consulting, formed in 1991 with one purpose -- to help. He has been helping clients such as IBM, McDonnell Douglas, Waste Management Inc., the U.S. Environmental Protection Agency, AT&T, Ameritech, Discover Card, Rockwell International, Bank of America and Nations Bank. He also helps local universities in the area of education and is author of the book "Developing NeXTSTEP Applications" ISBN 0-672-30658-1 published by SAM's Publishing.