CouchDB Reader Parameters

Select an existing connection, or Add Database Connection to define a new connection.

The new connection can be made visible only to the current user, or can be shared among multiple users.

The Service URL of the CouchDB dataset to access. This can be:

http://<host>:<port>/<root>[/<databasename>]

This parameter is required. The leading http:// is optional. Only the host name is required, usually followed by a port number. For example:

http://127.0.0.1:5984

mycouchddserver:5984

The values for these parameters specify the user name and password combination with which to log into the CouchDB server.

If left unspecified, only public database tables will be available to read.

After you have specified the database connection, click the Browse button to select tables for import. A connection window appears while the system compiles a table from the database.

Once the table list appears, you can select one or more tables, and then click OK to dismiss the window. The table name(s) will appear in the Table List field in the parameter box.

The parameter controls how the reader creates attributes from JSON document fields:

• One Level – Expand Arrays (default): The reader treats object fields as string attributes. Array fields at the top level of the JSON document are treated as list attributes.
• All Levels: The reader flattens all fields in the document as separate attributes. Fields within an object are treated as attributes with a ‘.’ in the attribute name. Fields within an array are treated as list attributes.
• One Level: The reader treats both object and array fields as string attributes.

Example:

	{
		“a”: 1,
		“object”: {
			“b”: 2,
			“c”: 3
		},
		“array”: [
			{
				“d”: 4
			},
			5
		]		
	}

If flattening mode is One Level – Expand Arrays:

• a : 1
• object : { “b”: 2, “c”: 3 }
• array{0} : { “d”: 4 }
• array{1} : 5

If flattening mode is All Levels, then the feature attributes would be:

• a : 1
• object.b : 2
• object.c : 3
• array{0}.d : 4
• array{1} : 5

If flattening mode is One Level:

• a : 1
• object : { “b”: 2, “c”: 3 }
• array : [ { “d”: 4 }, 5 ]

Specifies whether or not output features will have the couchdb_raw_json format attribute populated with the serialized representation of the JSON document.

If set to Yes, the couchdb_raw_json format attribute will automatically be exposed, and there will be no user attributes on the schema.

Specifies how many features are read from the server at a time.

Setting a high value can result in increased performance, as there can be significant overhead associated with each network request.

Use this parameter to expose Format Attributes in Workbench when you create a workspace:

• In a dynamic scenario, it means these attributes can be passed to the output dataset at runtime.
• In a non-dynamic scenario, you can use this parameter to expose additional attributes on multiple feature types.

Using the minimum and maximum x and y parameters, define a bounding box that will be used to filter the input features. Only features that intersect with the bounding box are returned.

If all four coordinates of the search envelope are specified as 0, the search envelope will be disabled.

Specifies the coordinate system of the search envelope if it is different than the coordinate system of the data. The coordinate system associated with the data to be read must always be set if this parameter is set.

If this parameter is set, the minimum and maximum points of the search envelope are reprojected from the Search Envelope Coordinate System to the reader’s coordinate system prior to applying the envelope.

When selected, this parameter removes any portions of imported features being read that are outside the Search Envelope.

The example below illustrates the results of the Search Envelope when Clip to Search Envelope is not selected (set to No) and when it is selected (set to Yes).

• No: Any features that cross the search envelope boundary will be read, including the portion that lies outside of the boundary.
• Yes: Any features that cross the search envelope boundary will be clipped at the boundary, and only the portion that lies inside the boundary will be read. The underlying function for the Clip to Search Envelope function is an intersection; however, when Clip to Search Envelope is selected, a clipping operation is also performed in addition to the intersection.