Data Consistency: Toward A Terminological Clarification

'Consistency' is an 'inconsistency' are ubiquitous term in data engineering. Its relevance to quality is obvious, since 'consistency' is a commonplace dimension of data quality. However, connotations are vague or ambiguous. In this paper, we address semantic consistency, transaction consistency, replication consistency, eventual consistency and the new notion of partial consistency in databases. We characterize their distinguishing properties, and also address their differences, interactions and interdependencies. Partial consistency is an entry door to living with inconsistency, which is an ineludible necessity in the age of big data.