MongoDB (beta notes)

A collection of notes on the state of Breeze + MongoDB integration.

TODO

We’re actively working on considering or resolving these issues and incorporating support where possible.

• Expands and navigation props that involve joins.
• Automatic server side validation.
• No OData functions except startsWith, endsWith, substringOf. Note: All comparison operators “>, >=, <, <=, ==” are supported.
• As of 1.4, only Guids stored as ‘strings’ are supported.

Issues and warnings

• MongoDB doesn’t support case insensitive sorts (except by creating a ‘lowercased’ version of a column). We need to set Breeze’s sorting to match (not yet done). Note: We do perform case insensitive searches because of the use of regex.
• MongoDB doesn’t support “embedded” functions, so most OData expressions involving functions get translated to MongoDB where clauses.
• MongoDB doesn’t support multipart keys.
• MongoDB doesn’t support primary key sharing between collections; so the idea of an Order and an InternationalOrder as different collections with the same key does not make sense.
• SQL data with padded strings behave differently on a query than MongoDB does. The ANSI standard requires padding for the character strings used in comparisons so that their lengths match before comparing them. MongoDB does not do this.
• Semantics for comparison with nulls are different between SQL and MongoDB – date1 > null in MongoDB , but not in SQL.
• MongoDB has no equivalent of timestamp or rowversion columns that are automatically generated on insert or update. (Except MongoDB ’s ObjectID).
• MongoDB has no concept of a computed column.
• MongoDB has no TimeSpan datetype.