HBuildKeyValue (Function)

bufSoughtVal is Buffer

// Build the composite key
bufSoughtVal = HBuildKeyValue(CUSTOMER, LASTNAME_FIRSTNAME, "MOORE", "Vince")

// Build a String/Integer composite key
bufSoughtVal = HBuildKeyValue(CUSTOMER, LASTNAME_CUSTNUM, "MOORE", 12128)

// Build an Integer/Integer composite key
bufSoughtVal = HBuildKeyValue(ORDER, ORDERID_ORDERID, 12119,593)

Syntax

<Result> = HBuildKeyValue(<Data file> , <Composite key> , <Value of components>)

<Result>: Buffer

Value of the composite key.

<Data file>: Character string (with or without quotes)

Name of HFSQL data file used.

<Composite key>: Character string (with or without quotes)

Name of the item corresponding to the composite key

<Value of components>: Character string

Value that will be assigned to each component of the composite key. This parameter has the following format:

<Component 1>, <Component 2>, ..., <Component N>

For example: "MOORE", "Vince".

Remarks

When to use HBuildKeyValue?

HBuildKeyValue must be used to perform searches on the linked keys (binary string) to composite keys.

Some examples:

FileA file:
COMPKEY is a composite key of FileA. Composition: FileA.LastName+FileA.FirstName
FileB file:
LINKEDCOMPKEY is a binary string key linked to FileA.COMPKEY

Performing a search on the value of the composite key:

HReadSeekFirst(FileB, LINKEDCOMPKEY, HBuildKeyValue(FileA, COMPKEY, ...
"Last name", "First name"))

bufKey is Buffer
bufKey = HBuildKeyValue(FileA, COMPKEY, "Last name", "First name")
HReadSeekFirst(FileB, LINKEDCOMPKEY, bufKey)

HReadSeekFirst(FileB, LINKEDCOMPKEY, FileA.COMPKEY)

if FILEA is positioned on the record that must be found in FILEB.

An array of values can be used instead of HBuildKeyValue:

HReadSeekFirst(FileB, LINKEDCOMPKEY, ["Last name", "First name"])

Generic search

When a generic search is performed, there is no need to define the values of all the components. Only the first n values are required (n being included between 1 and the number of key components, including bounds).

Building a composite key used in a filter with bounds

To build the value of a composite key, use HBuildKeyValue.

If the lower bound and the upper bound of the filter must be identical, the hMinVal and hMaxVal constants must be used to fill the bounds.
The following example is used to find all the records of Customer file corresponding to "Vince Moore":

HFilter(Customer, ...
HBuildKeyValue(Customer, LastNameFirstName, "Moore", "Vince") + hMinVal, ...
HBuildKeyValue(Customer, LastNameFirstName, "Moore", "Vince") + hMaxVal)
If the lower bound and the upper bound must be identical and if some key components are not specified, the hMinVal and hMaxVal constants must be used to fill the bounds.
The following example is used to find all the records of Customer file corresponding to "Moore":

HFilter(Customer, LastNameFirstName, ...
HBuildKeyValue(Customer, LastNameFirstName, "Moore" + hMinVal), ...
HBuildKeyValue(Customer, LastNameFirstName, "Moore" + hMaxVal))

Remarks:

hMinVal is equivalent to Charact(0)
hMaxVal is equivalent to Charact(255)

Building a composite key without using HBuildKeyValue

To build the value of a composite key without using HBuildKeyValue, you can:

Solution 1: Using an array of values (recommended solution):
For example:

HReadSeekFirst(FILEB, LINKEDCOMPKEY, ["Last name", "First name"])
Solution 2: Managing each type of component:
- entirely fill the text components with the hMinVal constant.
- convert the numeric components with HConvert.
For example:

MyCompositeKey = Complete(Customer.CustomerLastName, ...
Dimension(Customer.LastName), hMinVal) + ...
Complete(Customer.FirstName, Dimension (Customer.FirstName), hMinVal)

Remark: We recommend that you use HBuildKeyValue. The hMinVal constant is equivalent to Charact(0).

Component : wd250hf.dll