Handling Nulls In NoSQL & RDBMS Databases Compared
Handling nulls in various databases: MongoDB treats null as absent, SQL uses 3-value logic, PostgreSQL & YugabyteDB follow SQL standard, Oracle & SQL Server have workarounds, DynamoDB considers null as empty value.
NoSQL behavior: MongoDB SQL behavior: PostgreSQL and YugabyteDB A mix of both: Oracle Database You can create a unique index explicitly or implicitly with a unique constraint to ensure that a group of columns has no duplicates. However, how do you handle columns that are NULL or have no value? Is the lack of a value a simple indicator that you don't want to duplicate, or should it be treated as unknown and potentially equivalent to any value, thus not violating the unique constraint? I will consider the following three scenarios: NoSQL absence of value in a document, like in MongoDB SQL st...