1e41f4b71Sopenharmony_ci# Unified Data Definition Overview 2e41f4b71Sopenharmony_ci 3e41f4b71Sopenharmony_ciEfficient data interaction is critical for interaction between devices and applications. The Unified Data Management Framework (UDMF) provides unified data definitions for different applications and devices to reduce the costs in application and service data interaction. 4e41f4b71Sopenharmony_ci 5e41f4b71Sopenharmony_ciThe unified data definitions include [uniform type descriptors (UTDs)](uniform-data-type-descriptors.md) and [uniform data structs](uniform-data-structure.md). 6e41f4b71Sopenharmony_ci 7e41f4b71Sopenharmony_ci- UTD<br>A UTD is used to define data of the same type to eliminate data type ambiguity. It contains information, such as the data type ID and types to which the current data type belongs. UTDs are generally used to filter or identify the data type in file preview and file sharing. 8e41f4b71Sopenharmony_ci 9e41f4b71Sopenharmony_ci 10e41f4b71Sopenharmony_ci- Uniform data struct<br>A uniform data struct defines the data of a UTD. Uniform data structs allow unified parsing standards to be used in data interaction, which minimizes the adaptation workload. Uniform data structs are used for data interaction across applications and devices, such as, the drag-and-drop operations.