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The Persistent attribute hash table concept cover attributes of the following data types:
SdaiString / sdaiSTRING
SdaiInteger /sdaiINTEGER
SdaiInstance / sdaiINSTANCE
EdmiPackedDate / edmPACKED_DATE
FUNCTION xpxDefinePersistentAttrHashTable (entityId : GENERIC;
attrId : GENERIC;
options : INTEGER;
hashTableWidth : INTEGER;
stringLength : INTEGER)
status : INTEGER;
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The xpxDefinePersistentAttrHashTable function is used to define a persistent hash table to increase search speed in the database. A hash table is a persistent data structure in the database that speeds up the search for instances of one entity in one schema via the value of one attribute. Input parameters are defined for corresponding edmi-function.
The hash table is created when a data model of the specified schema is created and it is maintained during the entire lifetime of the model or until it is deleted. If there exist a data model based on the specified schema when the hash table is defined, this model do not get a hash table. In this case the model must be exported to a STEP file, deleted and recreated from the STEP file. Likewise is not an attribute hash table of data model removed if the attribute hash table definition is removed from the underlying schema of the data model.
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This function defines attribute hash table connected to the specified attribute in the specified schema.
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Related functions: xpxDefinePersistentAttrHashTableBN, xpfGetHashedAttrInstanceBN, xpxGetHashedAttrInstance, xpxGetHashedAttrInstancesBN and xpxGetHashedAttrInstances.
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The function is equivalent to the EDMinterfaceTM function edmiDefinePersistentAttrHashTable.
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See also:
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