Which of the following statements is true regarding callouts and DML operations?

In Salesforce, when a transaction includes data manipulation language (DML) operations and callouts, it is important to understand the order and relationship between these two actions. The statement that DML operations prevent callouts in the same transaction is accurate because of the transaction model Salesforce employs.

When a trigger or a synchronous Apex process involves DML, Salesforce requires that all the DML operations complete before any callouts occur. This means that if a transaction makes a DML operation, it cannot proceed to a callout until after those DML changes are fully processed. This is designed to maintain data integrity and ensure that operations that affect data do not conflict with external service calls that may rely on that data state.

Understanding this principle is crucial for designing effective integrations, as it will affect the flow of execution within processes and might necessitate structuring code to handle operations in a particular sequence. The transactional boundaries set by Salesforce ensure that developers are conscious of the timing of callouts and DML operations, allowing for predictable results in data processing and interactions with external systems.