1.3.3. HASH KEYS Hashing is the process of converting an input into a fixed-size output using a deterministic algorithm known as a hash function. In this sense, a hash key is a unique identifier generated by applying a hash function to a specific in- put data, like a business key (BK). For instance, consider a product’s BK, such as “123”, which upon hashing, might yield a result like MD5(123) = 202cb962 ac59075b964b07152d234b70, a 32-character string. This process is determin- istic, meaning that given the same input (123), the resulting output (202cb...) will consistently remain the same. In Data Vault, business keys are typically hashed to create fixed-length rep- resentations that enhance join performance. Given that keys may originate from diverse sources and be depicted in various formats, applying a hash- ing function standardizes them across the board. Hash keys offer fixed-size representations, which can streamline indexing and retrieval operations, particularly in traditional database environments. By ensuring a consistent length for join conditions and minimizing the computational overhead asso- ciated with variable-length keys, hash keys may significantly optimize query execution and overall system efficiency.
Customer Hashkey Source 1 720d115e73ef907...
Customer Business Key Source 1 CUST-987654
Customer Hashkey Source 2 12e0b9eb873ac01...
Customer Business Key Source 2 XYZ123456
Customer Hashkey Source 3 41e11a27864066f2...
Customer Business Key Source 3 2024-0001-ABC
Additionally, hashing is particularly advantageous when dealing with com- posite business keys, which can become lengthy and cumbersome. By re-
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