Final answer:
The entity identity problem in schema integration involves the challenge of combining real-world entities from multiple sources into a unified schema. This issue is critical in ensuring that records are correctly linked to their respective entities, avoiding duplication or data loss.
Step-by-step explanation:
The entity identity problem in schema integration refers to the difficulty of identifying and integrating real-world entities from multiple sources. When merging schemas from different databases, it is essential to recognize whether different records actually refer to the same entity in the real world. This problem arises because different systems might use varying identifiers for the same entity or the same identifiers for different entities, resulting in ambiguity.
To solve the entity identity problem, it is crucial to employ methods that can correctly match and merge records pertaining to the same real-world entities. Techniques such as data cleaning, integration middleware, and the use of a global identifier system can be involved to ensure accurate schema integration.
For example, if one database uses a person's social security number as a unique identifier, and another database uses a personal identification number, the schema integration process must reconcile which records correspond to the same individual to avoid duplication or data loss during integration.