1. A computer-implemented method for importing data for an Entity Relationship (E-R) model, the method comprising: receiving, by using a computer system, an exported E-R model data file and a data schema of the E-R model; determining a dependency type of an entity in the exported E-R model data file based on the data schema, wherein the dependency type corresponds to at least one of no correlation, weak correlation, and strong correlation; importing the entity in the exported E-R model data file based on the determined dependency type, wherein the importing the entity in the exported E-R model data file based on the determined dependency type includes: determining whether the imported entity with no correlation or weak correlation affects an entity recorded in a strong correlation table; responsive to the determined dependency type of the entity being at least one of weak correlation and no correlation, directly importing the entity; and responsive to the determined dependency type of the entity being strong correlation, storing the entity in the strong correlation table and deferring the importing of the entity until a minimum reference number of the strong correlation of the entity is satisfied; and responsive to the determination that the imported entity with no correlation or weak correlation affects the entity recorded in the strong correlation table, importing the entity recorded in the strong correlation table and deleting the entity recorded in the strong correlation table from the strong correlation table.