Json type is mapped to string in .Net. So, define
DeptSettings as
string in entity model.
public class Department {
public Guid Id { get; set; }
public int DeptId { get; set; }
public string DeptSettings { get; set; }
}
In the ApplicationDbContext file, explicitly specify the PostgreSQL data type by adding the following to your model's OnModelCreating:
protected override void OnModelCreating(ModelBuilder builder) {
builder.Entity<Department>().Property(d => d.DeptSettings).HasColumnType("json");
}
This way, the string will be cast to json and stored in the database.
Note: The value of the DeptSettings must be a string.