# Operations Once a projection has been prepared for usage in Novacura Flow, you can define what operation to use in a machine step. Simply select the connector in the machine step and choose "Select operation..." in the operation tree. There are a couple of different kinds of operations, typically a subset of the following kind of operations are available: * Create - creates a new entity * Read - query for entities * Update - update an existing entity * Delete - delete an entity * Actions - an operation that potentially changes the state of one or many entities * Functions - an operations that does not change state of any existing entity, i.e a pre-defined query, or create an entity with default values set * Code - a way for you to, in the context of the OData endpoint, write your own code in C# that does what you define. * Batch operations - multiple operations in one call {% hint style="warning" %} The OData connector supports a maximum of two levels of entity sets within the operation tree for a given projection. In this example, any additional entity sets under ***AddHandlingUnitTypesArray*** will not be visible in the operation tree. For entity sets that are in third level and beyond, you can use [Custom Request](https://help.novacuraflow.com/connectors/areas/business-systems/ifs-applications/ifs-odata/operations/custom-request) \ ![](https://529897662-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LtPTgZOYmpJka4jqs1v-3406065915%2Fuploads%2FW36GDkIolsmDsBlocmef%2Fimage.png?alt=media\&token=e87a1d51-fe10-4e1a-a2b7-32015a47a270)
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