You can import data from a relational database into a graph database using various strategies, including abandoning the relational database and migrating all data to the graph database, continuing to use the relational database for certain use cases while storing related data in a graph database, or duplicating data in both databases. The process typically involves extracting data from the relational database, such as by dumping tables or accessing them with a database driver, and then importing it into the graph database using tools like Neo4j's LOAD CSV command or the neo4j-import command-line bulk loader. These methods allow for flexible and efficient data import processes, enabling developers to choose the best strategy for their application goals and use cases.