Knowledge GraphKnowledge Graph describes concepts, entities and their relationships in the objective world in a structured way. Knowledge Graph is essentially a semantic network, in which nodes represent entities or concepts, and edges represent relationships between entities or concepts. Concepts refer to people's conceptual representation of objective things formed in the process of understanding the world, such as Country, City, etc. Entities are concrete things in the objective world, such as China, Beijing, etc. Relations describe the objective relationships between concepts or entities, such as the capital relationship that exists between China and Beijing.