What Is Hyperledger Composer Model File (*.cto)?

A Hyperledger Composer model file is a source code file that define business object types used in a business network: Participants, Assets, Transactions and Events.

A model file uses the CTO modeling language and the .cto file extension. Here is an example of a model file from the Basic Sample Business Network, ./models/sample.cto:

/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Sample business network definition.
 */
namespace org.example.basic

asset SampleAsset identified by assetId {
  o String assetId
  --> SampleParticipant owner
  o String value
  o String name
}

participant SampleParticipant identified by participantId {
  o String participantId
  o String firstName
  o String lastName
}

transaction SampleTransaction {
  --> SampleAsset asset
  o String newValue
}

event SampleEvent {
  --> SampleAsset asset
  o String oldValue
  o String newValue
}

⇒ Hyperledger Composer Script File

⇐ Business Network Source Code Architecture

⇑ Business Network Development Concepts

⇑⇑ Hyperledger Composer Tutorials