1. A method including: storing, in a data storage system, at least three objects, the objects including an object representing transformation of data, and at least two dataset objects representing stored data in datasets; storing, in a data storage system, data lineage information linking the at least two dataset objects to the object representing the transformation of data; computing summary data for data corresponding to the at least two dataset objects stored in the data storage system, including computing a percentage of data having valid or invalid values; generating a data lineage diagram that includes a visual representation of the data lineage information, in which the data lineage diagram includes at least two nodes that represent the at least two dataset objects, a third node that represents the object representing the transformation of data, and directed links between each of the at least two nodes that represent a dataset object and the third node that represents the object representing transformation of data, wherein the directed links represent flows of data between the dataset objects and the object representing transformation of data; and including in the data lineage diagram, a representation of the summary data in proximity to each of the nodes that represent the dataset objects, in which the nodes that represent the dataset objects are connected to directed links representing flows of data between the dataset objects and the object representing transformation of data, wherein the representation of the summary data is based on the percentage of the data in the respective dataset objects having valid or invalid values.