Understanding the Distinction Between One-to-One and Many-to-One Mapping in Hibernate

In TableB (phones), multiple phone numbers can be associated with a single person record. Similarly, in TableA (employee), there can be multiple employee records related to a single record in TableB (worklocation), which contains the address of the building where some of these employees work. The term cardinality in SQL refers to the uniqueness of data values in a database table column. One-to-one and one-to-many relationships refer to the uniqueness between two tables, with one-to-many meaning that TableA has one record related to many records in TableB, such as TableA (persons) having a set of unique person records.

Question:

Can you explain the contrast between the mapping techniques of one to one and many to one in Hibernate?


Solution:


To coincide with the overall explanation…

Within a relational database framework, a one-to-one mapping implies that a single record (or tuple) in the database is directly linked to another record in the database via a common column, which is usually a key of some sort.

In a one-to-many relationship, a single column would contain a value that corresponds to multiple rows in a different table.

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