SAMPLE: JDBC.exe Demonstrates How to Use JDBC/ODBC Bridge When Using Visual J++ (242921)

MORE INFORMATION

The following file is available for download from the Microsoft Download Center:
Release Date: Feb. 4, 2000

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.

File name	Use
JDBCFrontEnd.java	Main code
JDBCFrontEnd.sln	Workspace solution file
JDBCFrontEnd.vjp	Workspace project file
JDBCFrontEnd.class	Class file
JDBCFrontEnd.exe	Executable file

To run the JDBC sample application:

1. Extract the attached files into a folder named JDBCFrontEnd.
2. Compile and run the code. The sample application will populate a list box with all the DSN names on the computer.
3. Select the DSN and type in the username and password if required. Click Connect. You should see a confirmation message in the Status box.
4. Click any table name; the ListView control will be filled with data from that table. You can also connect to a database by typing in a proper JDBC URL and clicking Connect Using this URL. You can also retype your SQL query and click Requery to view the results.

NOTE: This sample application does not support table names with spaces in them.

The most important part of the JDBC sample application is the JDBCfrontend.java file. When the application starts, the PopulateDSNList function is called. This function uses native ODBC API calls to get the list of all DSNs on the system, as shown in the code segment below:

public void PopulateDSNList()
	{
		//int SQL_FETCH_NEXT = 1;
		//int SQL_MAX_DSN_LENGTH	= 32;
		int henv[] = {0};
		int NameLength1Ptr[] = {0};
		int NameLength2Ptr[] = {0};
		StringBuffer Description = new StringBuffer(1024);
		StringBuffer DSNName = new StringBuffer(1024);
		int rc;
		//Allocating Environment Handle
		rc = SQLAllocEnv(henv);
		
		rc = SQLDataSources(henv[0],SQLConstant.SQL_FETCH_NEXT,DSNName,
								   SQLConstant.SQL_MAX_DSN_LENGTH,NameLength1Ptr,
								   Description,256,NameLength2Ptr);
		while (rc!=SQLConstant.SQL_NO_DATA&&rc!=SQLConstant.SQL_ERROR)
		 
		{
			rc = SQLDataSources(henv[0],SQLConstant.SQL_FETCH_NEXT,DSNName,
								   SQLConstant.SQL_MAX_DSN_LENGTH,NameLength1Ptr,
								   Description,256,NameLength2Ptr);
			lbxDSNList.addItem((Object)DSNName.toString());
		}
	
	}
				

Here is the syntax for using JDIRECT in Java applications (in this case, SQLAllocEnv comes from ODBC32.dll):

/** @dll.import("ODBC32") */ 
	public static native short SQLAllocEnv( int henv[] );
				

Please download and refer to the JDBC.exe sample for the complete source code.