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  • When should HBuildKeyValue be used?
  • Generic search
  • Building a composite key used in a filter with bounds
  • Building a composite key without using HBuildKeyValue
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Stored procedures
HBuildKeyValue (Function)
In French: HConstruitValClé
ODBCNot available with this kind of connection
Builds the value of a composite key to implement a filter (HFilter) or to perform a search (HReadSeekFirst, HReadSeekLast, ...).
This function can be replaced by an array of values, easier to use. For example:
HReadSeekFirst(FileName, LINKEDCOMPKEY, ["Last name", "First name"])
Equivalent to:
HReadSeekFirst(FileName, LINKEDCOMPKEY, ...
        HBuildKeyValue(FileName, LINKEDCOMPKEY, "Last name", "First name"))
Tip: To browse a data file according to a composite key, use the FOR EACH statement on composite key (syntax 5).
See Composite keys for more details.
Reminder: The composite keys are binary strings whose content cannot be displayed directly.
Versions 15 and later
Android This function is now available for the Android applications.
New in version 15
Android This function is now available for the Android applications.
Android This function is now available for the Android applications.
Versions 17 and later
iPhone/iPad This function is now available for the iPhone/iPad applications.
New in version 17
iPhone/iPad This function is now available for the iPhone/iPad applications.
iPhone/iPad This function is now available for the iPhone/iPad applications.
Versions 18 and later
Android Widget This function is now available in Android Widget mode.
Universal Windows 10 App This function is now available in Windows Store apps mode.
New in version 18
Android Widget This function is now available in Android Widget mode.
Universal Windows 10 App This function is now available in Windows Store apps mode.
Android Widget This function is now available in Android Widget mode.
Universal Windows 10 App This function is now available in Windows Store apps mode.
Versions 21 and later
Universal Windows 10 App This function is now available in Universal Windows 10 App mode.
New in version 21
Universal Windows 10 App This function is now available in Universal Windows 10 App mode.
Universal Windows 10 App This function is now available in Universal Windows 10 App mode.
Note: From version 19, HFSQL is the new name of HyperFileSQL.
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(<File Name> , <Name of Composite Key> , <Value of Components>)
<Result>: Buffer
Value of the composite key.
<File Name>: Character string (with or without quotes)
Name of HFSQL data file used.
<Name of 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 should HBuildKeyValue be used?

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"))
or
bufKey is Buffer
bufKey = HBuildKeyValue(FILEA, COMPKEY, "Last name", "First name")
HReadSeekFirst(FILEB, LINKEDCOMPKEY, bufKey)
or
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))
Notes:
  • 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)
      Note: We recommend that you use HBuildKeyValue. The hMinVal constant is equivalent to Charact(0).
Components
WINDEVWEBDEV - Server codeReports and Queries wd230hf.dll
Windows Mobile wp230hf.dll
Java wd230java.jar
Linux wd230hf.so
Android wd230android.jar
Minimum required version
  • Version 9
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