`mongodrdl`¶

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Description
Options
Use

Description¶

mongodrdl¶

Note

The MongoDB Business Intelligence Connector and associated utilities are only available with MongoDB Enterprise.

mongodrdl produces a schema based on contents of one or more mongod collections and writes them out into .drdl files understood by mongobischema.

Options¶

Core Options¶

mongodrdl¶

--help¶: Returns information on the options and use of mongodrdl.

--version¶: Returns the mongodrdl release number.

--host <hostname><:port>, -h <hostname><:port>¶

Default: localhost:27017

Specifies a resolvable hostname for the mongod to which to connect. By default, the mongodrdl attempts to connect to a MongoDB instance running on the localhost on port number 27017.

To connect to a replica set, specify the replSetName and a seed list of set members, as in the following:

<replSetName>/<hostname1><:port>,<hostname2><:port>,<...>

You can always connect directly to a single MongoDB instance by specifying the host and port number directly.

--port <port>¶

Default: 27017

Specifies the TCP port on which the MongoDB instance listens for client connections.

--username <username>, -u <username>¶: Specifies a username with which to authenticate to a MongoDB database that uses authentication. Use in conjunction with the --password and --authenticationDatabase options.

--password <password>, -p <password>¶: Specifies a password with which to authenticate to a MongoDB database that uses authentication. Use in conjunction with the --username and --authenticationDatabase options.

--db <database>, -d <database>¶: Specifies a database from which to generate a .drdl schema file.

--collection <collection>, -c <collection>¶: Specifies a collection from which to generate a .drdl schema file. If you do not specify a collection, this option will use all collections in the specified database or instance.

--customFilterField <name>, -f <name>¶: Specifies the field name to add for a custom MongoDB filter. See Custom Filters for more details.

--out <path>, -o <path>¶

Default: Standard out.

Specifies the path where mongodrdl will write the schema file. To send the schema to standard output, specify “-” instead of a path.

--verbose <level>, -v <level>¶: Specifies that mongodrdl should provide more detailed log output. Include multiple times for more verbosity (e.g. -vvvvv), or specify a numeric value (e.g. --verbose=5).

--quiet¶: Hides all log output.

Authentication Options¶

--authenticationDatabase <dbname>¶: Specifies the database in which the user is created. See Authentication Database.

--authenticationMechanism <name>¶

Default: SCRAM-SHA-1

Specifies the authentication mechanism the mongodrdl instance uses to authenticate to the mongod or mongos.

Value	Description
SCRAM-SHA-1	RFC 5802 standard Salted Challenge Response Authentication Mechanism using the SHA1 hash function.
MONGODB-CR	MongoDB challenge/response authentication.
MONGODB-X509	MongoDB TLS/SSL certificate authentication.
GSSAPI (Kerberos)	External authentication using Kerberos. This mechanism is available only in MongoDB Enterprise.
PLAIN (LDAP SASL)	External authentication using LDAP. You can also use `PLAIN` for authenticating in-database users. `PLAIN` transmits passwords in plain text. This mechanism is available only in MongoDB Enterprise.

Custom Filters¶

You can add a special field to your schema that allows you to pass a custom MongoDB $match query string to your MongoDB instance.

mongodrdl offers the --customFilterField flag you can use to name such a custom filter field. Alternatively you can manually editing the DRDL file before importing it with mongobischema.

This custom filter field allows you to pass a native MongoDB query string down to MongoDB as the first $match stage of the aggregation pipeline, before any additional filters pushed down from SQL. The MongoDB query must be legal syntax, and can refer to any field in the collection, even if the fields were not exposed in the relational schema.

For an example, see Custom Filter.

Use¶

Generate a Schema¶

Given documents of the following shape in the collection abc in the database test:

{
    "_id": ObjectId("....")
    "close": 7.45,
    "detail": { "a": 2, "b": 3 }
}

You can use mongodrdl to generate a schema based on this collection by running the following command:

mongodrdl -d test -c abc -o schema.drdl

The generated schema file schema.drdl will look similar to the following:

schema:
- db: test
  tables:
  - table: abc
    collection: abc
    pipeline: []
    columns:
    - name: _id
      mongotype: float64
      sqltype: numeric
    - name: close
      mongotype: float64
      sqltype: numeric
    - name: detail.a
      mongotype: float64
      sqltype: numeric
    - name: detail.b
      mongotype: float64
      sqltype: numeric

Custom Filter¶

To use this field, specify the --customFilterField flag with the name you want this field to have:

mongodrdl [ other options ] --customFilterField "_MONGOFILTER" -o schema.drdl

Your DRDL file schema.drdl will include the following field in every generated table:

- name: _MONGOFILTER
  mongotype: mongo.Filter
  sqltype: varchar

To add the special MongoDB query stage to your standard SQL, use the following SQL syntax:

SELECT <normal>
   FROM <tablename>
   WHERE <normal conditions> AND
       "_MONGOFILTER"='{ <json string that represents query to use> }'

SELECT name,age
  FROM users
  WHERE active='t' AND
    "_MONGOFILTER"='{"addr":{"$elemMatch":{"city":"Springfield","state":"CA"}}}'

The MongoDB Business Intelligence Connector will translate the above SQL into the following MongoDB aggregation expression:

db.users.aggregate([
   {$match:{"addr":{"$elemMatch":{"city":"Springfield","state":"CA"}}},
   {$match:{"active":true}},
   {$project:{"name":1, "age":1}}
]);

You can use this custom filter in any Business Intelligence tool by filtering on your special field and providing the value to match as a single quoted string representing valid JSON. All quotes inside the JSON must be double quotes.

mongodrdl¶