The Table Component Object

Currently, a lot of data is being stored in flat files for Web applications. In some cases this is a good idea, because not all data fits into a relational model. However, the hierarchical structure of the UNIX file system may be combined with the use of powerful UNIX file system commands to simulate a "database" which isn't easily expressed in a relational model. The absence of tools to hook databases to Web applications has forced the use of flat files in cases where a relational database would be more appropriate.

A problem with using flat files is the lack of a high-level, industry standard language like SQL. Without such a language, you lose data independence; you must write functions to support each additional query capability, and you have no index capability for searching large tables. In these cases you are building a legacy.

Suppose you wish to query for all employees who live in Utah, or all employees who earn more than $30,000, or all employees who live in Utah and earn more than $30,000, etc. The table component provides a tool for such needs.

The following sketch example shows how to use the Table Component.

1. Start Sapphire. Either use an existing project or make a new one.

2. Choose a start-up HTML file with either an Anchor or Form for an Activator with at least an Input Element and a Submit Button. The directory, contrib/table_ex, in the Sapphire/Web distribution, contains an example start-up HTML file with both an Anchor, a Form, and customization files.

3. Add the start-up HTML file to the project.

4. Bind that Anchor Activator to the NULL object using the Object Bind Editor. Choose Apply.

5. Choose Edit|Activator Code ... Enter the following code in the "Function Initialization Code" text box:

SaVaHtmlTable("SERVERNAME", "pubs2", 
	"dbo.titles", SGESYBASE,
	SA_TABLE_TEMPLATE,
	NULL);
return;

For Oracle:

SaVaHtmlTable("ORACLE", "DATABASENAME", 
	"SCOTT.TITLES", SGEORACLE,
	SA_TABLE_TEMPLATE,
	NULL);
return;

For Informix:

SaVaHtmlTable("SERVERNAME", "pubs2",
	"informix.titles", SGEINFORMIX,
	SA_TABLE_TEMPLATE,
	NULL);
return;

The SaVaHtmlTable function takes a variable argument list of options which MUST BE null terminated. The constant SA_TABLE_TEMPLATE is defined to be the option string:

"SaHtmlTable.Template : True"

Now choose OK in the activator code window and then OK in the Object Bind Editor. Next choose the Edit|Options menu from the project window. Set your start-up document in the Project Category. Also set the username and password for your database in your Test category, if not already set appropriately. Save your options as well as your project. Now Save, Build and Test your project. Click on the anchor. You will note that the Notes textbox is rather long. It is defined to be varchar 255. Also notice that the hotlist strings are too long. Your table may be customized to remedy these problems as follows:

Add the HTML customization file

titles_tab.html 

or

TITLES_tab.html 

The differences between Sybase, Oracle, and Informix are in case sensitivity. Bind the Form Activator to the NULL object using the Object Bind Editor; choose Apply. Now choose Edit |Activator Code... Enter the following code in the Function Initialization Code text box:

For Sybase:

SaVaHtmlTable("SERVERNAME", "pubs2",
	SaGetInputValue("TABLE_NAME"), SGESYBASE,
	SA_TABLE_TEMPLATE,
	NULL);
return;

For Oracle:

SaVaHtmlTable("ORACLE", "DATABASENAME",
	SaGetInputValue("TABLE_NAME"), SGEORACLE,
	SA_TABLE_TEMPLATE,
	NULL);
return;

For Informix:

SaVaHtmlTable("SERVERNAME", "pubs2",
	SaGetInputValue("TABLE_NAME"), SGEINFORMIX,
	SA_TABLE_TEMPLATE,
	NULL);
return;

The Table Component has some limitations. It does not work with BLOB data. It also assumes that the table exists without relations to other tables. If you have set up certain integrity rules, then this may not be a problem. The source code for the Table Component can be found in the client/src directory of the Sapphire/Web distribution, and the include files are found in the include directory. The source code shows how you can use the Sapphire/Web API to deliver powerful components to your developers/user and other parts of your organization.

If you wish to learn more about the Table Component and how to make wide use of it, see the Bluestone demo at:

http://www.bluestone.com/sapphire/table/tdemo.html

Note: Make sure you read Instructions, on the demo Web page, which also serves as a white paper.