What is schema-free DB

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Schema freedom

A database schema defines the structure of the data, such as the number and type of attributes of a table in a relational database management system. A database management system that supports schemes usually rejects data that does not correspond to this structure. This means that the applications can rely on at least a formal data quality.

A schema-free database is also able to store less structured data. Document stores and wide column stores are typical representatives of this class. A data record there can have columns with previously undefined names and types, and the number of columns can also be different for each data record.

Of course, schema-free databases are particularly suitable when the data to be processed does not have a natural, uniform structure. For example, if you want to model the goods that are offered by a retailer, then a large number of items will have completely different attributes, such as hard drives and monitors. A schema-free storage could be the most suitable variant here, which does not require any effort in data modeling even with newly added types of articles. The application must of course still be able to deal with new structures.

The lack of a schema gives you more flexibility, but you do not have to check the data by the DBMS.