Knowledge graphs have become the cornerstone of artificial intelligence. The construction and publication of large-scale knowledge graphs in various domains have posed new challenges on the data management of knowledge graphs. In this paper, in accordance with the structural and operational elements of a data model, the current theories, methods, technologies, and systems of knowledge graph data management are surveyed. First, the paper introduces knowledge graph data models, including the RDF graph model and the property graph model, and also introduces 5 knowledge graph query languages, including SPARQL, Cypher, Gremlin, PGQL, and G-CORE. Second, the storage management schemes of knowledge graphs are presented, including relational-based and native approaches. Third, three kinds of query operations are discussed, which are graph pattern matching, navigational, and analytical queries. Fourth, the paper introduces mainstream knowledge graph database management systems, which are categorized into RDF triple stores and native graph databases. Meanwhile, the state-of-the-art distributed systems and frameworks that are used for processing knowledge graphs are also described, and benchmarks are presented for knowledge graphs. Finally, the future research directions of knowledge graph data management are put forward as well.