1. A method for open data marketplace, comprising: identifying, by a processor, one or more data attributes of data objects used by a plurality of applications registered with a shared data management system provided on software as a service platform, said one or more data attributes specified in data schemas of the plurality of applications; mapping, by the processor, said one or more data attributes to a data model to create a first set of mapped data, the data model being a common data object schema provided by the shared data management that allows data trading and viewing of the data attributes in said data model, the mapping comprising mapping attribute names of said one or more data attributes in the data schemas of the plurality of applications to attribute names of the common data object schema; receiving from the plurality of applications data content associated with the mapped attribute names and storing the data content in a shared data management database providing the common data object schema; augmenting, by the processor, said first set of mapped data with additional data imported into the shared data management system from other data locations to create an augmented set of mapped data; receiving, by the processor, one or more of a second set of mapped data from one or more second shared data management systems associated respectively with one or more shared data management networks; enabling, by the processor, of composing of a data set by combining and cleansing one or more of said first set of mapped data, said second set of mapped data, and said augmented set of mapped data, the combining and cleansing comprising at least removing duplicated attributes with different names from different applications of the plurality of applications, and keeping different attributes with same names from different applications of the plurality of applications, wherein the data set is composed to comprise attribute names from the common data object schema, and generating a consolidated database of the plurality of applications; and offering, by the processor, said composed data set in a digital marketplace by an auction, wherein the plurality of applications deployed on the software as a service platform are allowed to exchange one or more data objects of the composed data set via the digital marketplace auction by requesting data trades and accepting data trade requests, wherein a data export service allows an application requesting data trade to access the one or more data objects by at least providing a private data storage wherein the application can read the one or more data objects by data query language or by providing a set of application programming interface to allow the application to directly read the one or more data objects in the shared data management system, the data trades between the plurality of applications integrating the plurality of applications that are running separately on at least one hardware processor.