What is a host variable? When a program retrieves data, the values are put into data items defined by your program and specified with the INTO clause of a SELECT INTO or FETCH statement. The data items are called host variables.
How is a host variable identified in an embedded SQL statement? By the colon (:) found preceding the field name.
If the selection criteria will return only one result row, the SELECT INTO statement can be used. The following code is an example of the SELECT INTO structure:
C+ Select MIN(SALARY), AVG(SALARY), MAX(SALARY)
C+ Into :MinSalary, :AvgSalary, :MaxSalary
C+ From EMPMSTR
C+ Where EDLEVEL > :EducLevel
C/End-Exec
If the selection criteria will return more that one row, the FETCH statement must be used. The following code is an example of the FETCH structure:
C+ Fetch Cursor1 Into
C+ Into :RptLastName, :RptFirstName, :RptSalary
C/End-Exec
In conjunction with the FETCH statement, a cursor must be defined, and the cursor must be opened prior to the FETCH and closed after the FETCH.
Now you're asking, "What is a cursor?" It is a declaration of an SQL SELECT statement without the INTO that will potentially return more than one row of data. The following code is an example of an SQL cursor declaration:
C+ Declare Cusror1 Cursor For
C+ Select LASTNAME, FIRSTNAME, SALARY
C+ From EMPMSTR
C+ Where EMPNO = :ScnEmp#
C/End-Exec
In the preceding code samples, you have seen two of the three ways that host variables are used in embedded SQL:
In a WHERE clause
- As a receiving area for column values (named in an INTO clause)
The third way that a host variable is used is as a value in a SELECT clause. The following code is an example of this:
C+ Select LASTNAME, SALARY, :Raise, SALARY + :Raise
C+ Into :RptLastName, :RptSalary, :RptRaise, :RptNewSalary
C+ From EMPMSTR
C+ Where EMPNO = :ScnEmp#
C/End-Exec
With this basic knowledge, using host variables within embedded SQL is made simple.
More information is required to use embedded SQL. The additional information on host variables and embedded SQL can be found on the iSeries Information Center. Select the region, language, and operating system version. Then, navigate to the link for Programming>SQL and select the SQL Programming with Host Languages book.
Paul Weyer is a consultant with New Resources Consulting. He has worked on the iSeries (AS/400) since 1987. His background includes both hardware configuration/installation and software development. Paul is a subject matter expert (SME) with COMMON in the areas of LPAR, IT optimization, performance, availability/business continuity, iSeries operations, and "Managing Beyond Your Server." His language background includes both COBOL and RPG, and he has been using SQL since 1987. Email Paul at
More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.
TRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now! Request Now.
Forms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.
Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:
Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.
IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn:
LATEST COMMENTS
MC Press Online