The HASH_LOAD function retrieves a row of data from a Hash Table. Hash Tables allow data to be stored in-memory for fast, efficient retrieval during processing. They are most commonly used for lookups to reference data vs selecting data from a relational table in a database.
Category
Specialized
Syntax
HASH_LOAD(hash_table, hash_key)
Parameters and Descriptions
| Parameter | Description |
|---|---|
| hash_table | The name of a previously declared hash_table. |
| hash_key | This parameter specifies the value that will be compared against the key of the hash_table. The search value may be a field/column of a source datastore, a literal value (i.e. ABC), a variable or the result of another Function. |
Example
Determine if a row exists in hash table H_EMPTBL1 using source field CDCIN.EMPNUM as the key. Code the statement something like this.
IF ISNULL(HASH_LOAD(H_EMPTBL1, CDCIN.EMPNUM)) = TRUE
DO
...
ENDSearch the H_EMPTBL1 hash table for a row with a key matching the value of EMPNUM. Retrieve data from a row in the H_EMPTBL1 hash table, you would code the statement something like this.
V_EMPDATA = HASH_LOAD(H_EMPTBL1, EMPNUM)
IF ISNULL(V_EMPDATA) = TRUE
CALLPROC(no_entry_found_procedure)
ELSE
{
target.SSN = LEFT(V_EMPDATA, 9) -- EXTRACT SSN
target.LNAME = MID(V_EMPDATA,10,30) -- EXTRACT LAST NAME
target.DEPT = RIGHT(V_EMPDATA,10) -- EXTRACT DEPT
}