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- Overview
- Method 1: Path functions
- Example
- Method 2: Instruction FOR EVERYTHING
- Code example
How do I run through a data file?
Two methods can be used to perform the full browse of a data file: This method uses the following WLanguage functions to loop through data files: In this method: - HReadFirst is used to access the first record according to the search key.
- HReadNext is used to access the next record (in the order of search key).
- HOut is used to find out whether the end of file was reached.
Example // Browse all records of Customer file
// sorted by customer name.
HReadFirst(CUSTOMER, CustomerName)
WHILE NOT HOut(CUSTOMER)
// Process the CUSTOMER record
HReadNext(CUSTOMER, CustomerName)
END
Method 2: Instruction FOR EVERYTHING The FOR EACH statement loops through the records of a data file. In our case, this statement will be used to read the records found in a data file. The FOR EACH instruction expects the following parameters: - the name of the data file to loop through.
- the name of the index (or key) to sort the records.
The first record and the next record are read by the FOR EACH statement. There is no need to use the HReadXXX functions. Note The word DESC can be used to perform a Reverse run. Code example
FOR EACH CUSTOMER ON CustomerName
END
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