This code system http://hl7.org/fhir/restful-interaction defines the following codes:

LvlCodeDefinition
1read Read the current state of the resource.
1vread Read the state of a specific version of the resource.
1update Update an existing resource by its id (or create it if it is new).
1patch Update an existing resource by posting a set of changes to it.
1delete Delete a resource.
1history Retrieve the change history for a particular resource, type of resource, or the entire system.
2  history-instance Retrieve the change history for a particular resource.
2  history-type Retrieve the change history for all resources of a particular type.
2  history-system Retrieve the change history for all resources on a system.
1create Create a new resource with a server assigned id.
1search Search a resource type or all resources based on some filter criteria.
2  search-type Search all resources of the specified type based on some filter criteria.
2  search-system Search all resources based on some filter criteria.
2  search-compartment Search resources in a compartment based on some filter criteria.
1capabilities Get a Capability Statement for the system.
1transaction Update, create or delete a set of resources as a single transaction.
1batch perform a set of a separate interactions in a single http operation
1operation Perform an operation as defined by an OperationDefinition.
<status value="active"/><experimental value="false"/><publisher value="FHIR Project"/><description value="The set of interactions defined by the RESTful part of the FHIR specification."/><jurisdiction><coding><system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/><code value="001"/><display value="World"/></coding></jurisdiction><caseSensitive value="true"/><valueSet value="http://hl7.org/fhir/ValueSet/restful-interaction"/><hierarchyMeaning value="is-a"/><content value="complete"/><concept><code value="read"/><display value="read"/><definition value="Read the current state of the resource."/></concept><concept><code value="vread"/><display value="vread"/><definition value="Read the state of a specific version of the resource."/></concept><concept><code value="update"/><display value="update"/><definition value="Update an existing resource by its id (or create it if it is new)."/></concept><concept><code value="patch"/><display value="patch"/><definition value="Update an existing resource by posting a set of changes to it."/></concept><concept><code value="delete"/><display value="delete"/><definition value="Delete a resource."/></concept><concept><code value="history"/><display value="history"/><definition value="Retrieve the change history for a particular resource, type of resource, or the entire system."/><concept><code value="history-instance"/><display value="history-instance"/><definition value="Retrieve the change history for a particular resource."/></concept><concept><code value="history-type"/><display value="history-type"/><definition value="Retrieve the change history for all resources of a particular type."/></concept><concept><code value="history-system"/><display value="history-system"/><definition value="Retrieve the change history for all resources on a system."/></concept></concept><concept><code value="create"/><display value="create"/><definition value="Create a new resource with a server assigned id."/></concept><concept><code value="search"/><display value="search"/><definition value="Search a resource type or all resources based on some filter criteria."/><concept><code value="search-type"/><display value="search-type"/><definition value="Search all resources of the specified type based on some filter criteria."/></concept><concept><code value="search-system"/><display value="search-system"/><definition value="Search all resources based on some filter criteria."/></concept><concept><code value="search-compartment"/><display value="search-compartment"/><definition value="Search resources in a compartment based on some filter criteria."/></concept></concept><concept><code value="capabilities"/><display value="capabilities"/><definition value="Get a Capability Statement for the system."/></concept><concept><code value="transaction"/><display value="transaction"/><definition value="Update, create or delete a set of resources as a single transaction."/></concept><concept><code value="batch"/><display value="batch"/><definition value="perform a set of a separate interactions in a single http operation"/></concept><concept><code value="operation"/><display value="operation"/><definition value="Perform an operation as defined by an OperationDefinition."/></concept></CodeSystem>