free barcode generator source code in vb.net Handling Error Conditions in Software

Generate USS Code 128 in Software Handling Error Conditions

Handling Error Conditions
Code 128A Decoder In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Create Code 128 Code Set C In None
Using Barcode maker for Software Control to generate, create Code 128 image in Software applications.
When an application program uses Embedded SQL or a SQL API for database processing, the application program is responsible for handling errors that arise. Error status codes are returned to the application program, and more error information is typically available through additional API calls or access to an extended diagnostics area. When database processing takes place within a stored procedure, the procedure itself must handle errors. Transact-SQL provides error handling through a set of global system variables. The specific error-handling variables are only a few of well over 100 system variables that provide information on the state of the server, transaction state, open connections, and other database configuration and status information. The two most useful global variables for error handling are: I @@@ERROR. Contains error status of the most recently executed statement batch I @@@SQLSTATUS. Contains status of the last fetch operation The normal completion values for both variables are zero; other values indicate various errors and warnings. The global variables can be used in the same way as local variables within a Transact-SQL procedure. Specifically, their values can be checked for branching and loop control. Oracle s PL/SQL provides a different style of error handling. The Oracle DBMS provides a set of system-defined exceptions, which are errors or warning conditions that can arise during SQL statement processing. Within an Oracle stored procedure (actually, any Oracle statement block), the EXCEPTION section tells the DBMS how it
Code 128 Decoder In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
Code 128C Maker In C#
Using Barcode creator for .NET framework Control to generate, create Code 128B image in VS .NET applications.
20:
Encoding Code 128 Code Set C In Visual Studio .NET
Using Barcode maker for ASP.NET Control to generate, create Code 128A image in ASP.NET applications.
Encode USS Code 128 In Visual Studio .NET
Using Barcode creation for .NET Control to generate, create Code 128C image in .NET applications.
Database Processing and Stored Procedures
Code 128A Printer In VB.NET
Using Barcode maker for Visual Studio .NET Control to generate, create Code 128 Code Set A image in Visual Studio .NET applications.
Creating Barcode In None
Using Barcode generation for Software Control to generate, create barcode image in Software applications.
should handle any exception conditions that occur during the execution of the procedure. There are over a dozen different predefined Oracle-detected exception conditions. In addition, you can define your own exception conditions. Most of the previous examples in this chapter don t provide any real error-handling capability. Figure 20-16 shows a revised version of the Oracle stored function in Figure 20-7. This improved version detects the specific situation where the supplied customer number does not have any associated orders (that is, where the query to calculate total orders returns a NO_DATA_FOUND exception). It responds to this situation by signaling back to the application program an application-level error and associated message. Any other exception conditions that arise are caught by the WHEN OTHERS exception handler.
Code 128C Generation In None
Using Barcode drawer for Software Control to generate, create Code 128C image in Software applications.
EAN13 Drawer In None
Using Barcode drawer for Software Control to generate, create EAN13 image in Software applications.
SQL TODAY AND TOMORROW
Data Matrix ECC200 Printer In None
Using Barcode creator for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
Making Code 3 Of 9 In None
Using Barcode generation for Software Control to generate, create ANSI/AIM Code 39 image in Software applications.
/* Return total order amount for a customer */ create function get_tot_ords(c_num in integer) return number(16,2) as /* Declare one local variable to hold the total */ declare tot_ord number(16,2); begin /* Simple single-row query to get total */ select sum(amount) into tot_ord from orders where cust = c_num; /* return the retrieved value as fcn value */ return tot_ord; exception /* Handle the situation where no orders found */ when no_data_found then raise_application_error (-20123, Bad cust# ); /* Handle any other exceptions */ when others then raise_application_error (-20199, Unknown error ); end;
Create Identcode In None
Using Barcode generation for Software Control to generate, create Identcode image in Software applications.
Code39 Generator In Visual Studio .NET
Using Barcode generation for .NET framework Control to generate, create ANSI/AIM Code 39 image in .NET applications.
Figure 20-16.
GTIN - 13 Scanner In Visual Basic .NET
Using Barcode reader for VS .NET Control to read, scan read, scan image in .NET applications.
Scan GTIN - 13 In Visual C#
Using Barcode scanner for .NET framework Control to read, scan read, scan image in .NET applications.
PL/SQL stored function with error handling
UPC - 13 Reader In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
Encoding Matrix 2D Barcode In C#
Using Barcode creation for .NET framework Control to generate, create Matrix Barcode image in VS .NET applications.
SQL: The Complete Reference
Create UPC-A Supplement 5 In Java
Using Barcode encoder for Java Control to generate, create GTIN - 12 image in Java applications.
Encoding Code39 In Visual C#
Using Barcode generation for Visual Studio .NET Control to generate, create USS Code 39 image in VS .NET applications.
The Informix SPL takes a similar approach to exception handling. Figure 20-17 shows the Informix version of the stored function, with Informix-style exception handling. The ON EXCEPTION statement is a declarative statement and specifies the sequence of SQL statements to be executed when a specific exception arises. A comma-separated list of exception numbers may be specified.
/* Return total order amount for a customer */ create function get_tot_ords(c_num in integer) returning money(16,2) /* Declare one local variable to hold the total */ define tot_ord money(16,2); /* Define exception handler for error #-123 and -121 */ on exception in (-121, -123) /* Do whatever is appropriate here */ . . . end exception; on exception /* Handle any other exceptions in here */ . . . end exception; begin /* Simple single-row query to get total */ select sum(amount) into tot_ord from orders where cust = c_num; /* Return the retrieved value as fcn value */ return tot_ord; end function;
Figure 20-17.
Copyright © OnBarcode.com . All rights reserved.