Multi-source heterogeneous database fusion system and data query method thereof

The invention provides a multi-source heterogeneous database fusion system and a data query method thereof. The system comprises a database layer, a data fusion layer and a uniform application layer. The database layer is composed of heterogeneous databases and agencies of the heterogeneous databases. The data fusion layer is used for fusing information of all heterogeneous data sources, and is responsible for data access of the heterogeneous data sources and coordinating the information of all the data sources, and specifically comprises a metadata data base (DB), a metadata manager, a comprehensive wrapper, a mediator, an application layer access uniform interface and a heterogeneous database uniform interface. The uniform application layer is the user of the heterogeneous database fusion system and can have access to shared data resources of the heterogeneous databases by fusing middle layers. The multi-source heterogeneous database fusion system and the data query method of the multi-source heterogeneous database fusion system solve the problems in heterogeneous database fusion and overcome the defects of an existing database fusion technology. The system can conduct transparent query on all the heterogeneous databases on the condition that local databases are not affected, and the maintenance cost of the system is reduced.