FAQ: The MongoDB Connector for BI¶

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Does the MongoDB Connector for BI store any data?
In what order does query processing happen?
What SQL statements get pushed down to MongoDB?
How do I skip data incompatible with my DRDL type definition?
Is there any syntax validation tool for DRDL?
How does the MongoDB Connector for BI process dates?
How do I use TLS with the MongoDB Connector for BI?
How do I use LDAP authentication with the MongoDB Connector for BI?

Does the MongoDB Connector for BI store any data?¶

No. The MongoDB Connector for BI is an interface into your MongoDB database. It stores only user information and MongoDB connection string information imparted by mongobiuser, and the schema defined by a DRDL file.

In what order does query processing happen?¶

Changed in version 1.1.1: The MongoDB Connector for BI now processes ORDER BY clauses.

The MongoDB Connector for BI will process a query in the following order:

The $match stage from a custom filter,
The aggregation pipeline from the DRDL file,
Any $match stages from the WHERE clause,
Any $sort stages from the ORDER BY clause,
The $project stage from the SELECT clause.

What SQL statements get pushed down to MongoDB?¶

Changed in version 1.1.1: The MongoDB Connector for BI now pushes ORDER BY clauses down to MongoDB.

The MongoDB Connector for BI will push SELECT projection terms, WHERE conditions including the IN operator, and the ORDER BY clause down to MongoDB.

You can push JOIN, GROUP BY, and other clauses down to MongoDB using the pipeline field of your DRDL file and custom filters.

How do I skip data incompatible with my DRDL type definition?¶

If documents in a collection contain different data types for a field, you may wish to filter for a specific data type. To accomplish this, you can include a $match stage at the beginning of the pipeline in your DRDL table definition.

For example, to match only documents containing a number in the grade field, use the following pipeline stage:

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"$match": { "grade": { "$type": "number" } }

If you are unwinding an array field that contains different data types, then to filter the array for a specific data type, put the $match stage after the $unwind.

Is there any syntax validation tool for DRDL?¶

DRDL files use the YAML syntax. Any YAML validator such as https://yaml-online-parser.appspot.com/ can help you check your DRDL files.

How does the MongoDB Connector for BI process dates?¶

The MongoDB Connector for BI will correctly process BSON date data by mapping it to the SQL datetime type. For example:

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db.data.save({ date: new Date() })

However, if you store date data as a string, MongoDB Connector for BI will treat it as a string rather than as a date. For example, MongoDB Connector for BI will treat the following as a string:

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db.data.save({ date: '32-FEB-2015' })

How do I use TLS with the MongoDB Connector for BI?¶

If the MongoDB instance you are connecting to uses SSL/TLS, you must use the ssl=true option in the PyMongo connection string.

For example, when using mongobiuser:

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mongobiuser create bradbi \
            'mongodb://brad:password@localhost:27017/?ssl=true'

To specify a TLS CA root certificate, use the ssl_ca_certs option. To specify a client certificate, use the ssl_certfile option. For example:

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mongobiuser create bradbi \
            'mongodb://localhost:17017/?ssl=true&ssl_ca_certs=/certs/ca.pem&ssl_certfile=/certs/mongodb_client.pem'

How do I use LDAP authentication with the MongoDB Connector for BI?¶

If you are connecting to a MongoDB instance that uses LDAP for user authentication, you must specify the authMechanism=PLAIN and authSource=$external connection string options. For example:

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mongobiuser create bradbi \
            'mongodb://USERNAME:PASSWORD@localhost:27017/?authMechanism=PLAIN&authSource=$external'

Important

You must surround your connection string in single quotes, as in the example. This prevents your shell from trying to expand $external with an empty string.

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