1. Maintaining and assuring the accuracy and consistency of data over ist entire life cycle.
2. Data integrity means that data can not be removed or modified by unauthorized persons during processing or transmission. It ensures the consistency, correctness and trustworthiness of the data during their entire lifetime and ensures that the relevant data of a data stream can be reconstructed.
https://www.techopedia.com/definition/811/data-integrity-databases (1.); http://www.businessdictionary.com/definition/data-integrity.html (2.)