Speaker Deck

Entity Relationships in a Document Database at ZendCon 2012

by Bradley Holt

Published October 25, 2012 in Programming

Unlike relational databases, document databases like CouchDB and MongoDB do not directly support entity relationships. This talk will explore patterns of modeling one-to-many and many-to-many entity relationships in a document database. These patterns include using an embedded JSON array, relating documents using identifiers, using a list of keys, and using relationship documents. This talk will explore how these entity relationship patterns equate to how entities are joined in a relational database. We'll take a look at the relevant differences between document databases and relational databases. For example, document databases do not have tables, each document can have its own schema, there is no built-in concept of relationships between documents, views/indexes are queried directly instead of being used to optimize more generalized queries, a column within a result set can contain a mix of logical data types, and there is typically no support for transactions across document boundaries.