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HDescribeKey (Function) In french: HDécritClé
 Warning
HDescribeKey is kept for backward compatibility (this function will still be supported in the forthcoming version). From version 8, to describe a key, you must: - Declare an item object.
- Define all the properties of the item with the HFSQL properties.
- Use HDescribeItem to validate the item creation.
Below is the documentation of HDescribeKey, available in WINDEV 5.5
| Purpose Describe a simple or composite key in a temporary data file in Hyper File formatSyntax HDwrittenKey(<LogicalNameHF File>,<KeyName> [,<KeyList> [,<Double>]])- <LogicalNameHFFile> is a character string containing the name of the logical data file
- <NameKeyItem> is a character string containing the name of the key (up to 100 characters)
- <KeyItemList> is an optional character string containing the list of items found in the key.
- For a composite key, the items are separated by a comma in <ListKeyItem>: <NameItem1>, <NameItem2>, ...
- For a simple key, <Item List> contains the name of the key.
- <Duplicates> is an optional boolean used to find out whether the key is unique or multiple:
- set to True for multiple key (with duplicates)
- set to False for a unique key
By default, <Duplicate> is set to True.
Details The key is built according to the parameters passed to HDescribeKey.If <ListKeyItem> is not specified, <NameKeyItem> must be a file item If several keys are specified, the simple keys must be defined before the composite keys. The error HF 508 occurs if a composite key is described before a simple key. <Duplicates> is set to True by default. Therefore, if <Duplicate> is not specified, the key is a multiple key. Notes - The data file must have been described by HDescribeFile.
- The items included in the key must have been described beforehand by HDescribeItem.
- To describe a unique simple key, the syntax is as follows:
HDescribeKey(<FileName>,<Key_Name>, <Key Name>, False)
- The function HDescribeKey cannot be used to describe an a data file key that was created with the description editor of HEX@ data.
- HDescribeKey does not exist in external language.
- HDescribeKey must not be called after one of the following functions used on the same data file: HOpen, HCreation or HCreationIfNotFound.
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