System.StackOverflowException was unhandled error

I am fairly new to repositories and mock repositories, so I would like help understanding what this error means exactly and how to avoid it. I have looked at other posts and done my research but they are too specific to their errors. The code that is breaking is

public int PersistComponentDb(Core.Models.ComponentDbModel componentDb)
{
    return PersistComponentDb(componentDb);
}

I understand that the function is calling itself but how do I stop it from doing that? It is persisting a mock repository, and the hard coded values look like this

public DataTable GetComponentDbs(int? forComponentId = null, int? forDbServerId = null, int? forEntityId = null)
{
    DataTable componentDbs = new DataTable();
    componentDbs.Columns.Add("ComponentDbID", typeof(Int32));
    componentDbs.Columns.Add("ComponentID", typeof(Int32));
    componentDbs.Columns.Add("DbServerID", typeof(Int32));
    componentDbs.Columns.Add("EntityID", typeof(int));
    componentDbs.Columns.Add("SecurableGuid", typeof(String));
    componentDbs.Columns.Add("FriendlyName", typeof(String));
    componentDbs.Columns.Add("DbName", typeof(String));
    componentDbs.Rows.Add(new object[] { 1, 2, 2, 3822, "SecureableGuid", "Test #1", "DB #1" });
    return componentDbs;
}

public DataRow GetComponentDb(int id)
{
    DataTable componentDbs = new DataTable();   
    componentDbs.Columns.Add("ComponentDbID", typeof(Int32));
    componentDbs.Columns.Add("ComponentID", typeof(Int32));
    componentDbs.Columns.Add("DbServerID", typeof(Int32));
    componentDbs.Columns.Add("EntityID", typeof(Int32));
    componentDbs.Columns.Add("SecurableGuid", typeof(String));
    componentDbs.Columns.Add("FriendlyName", typeof(String));
    componentDbs.Columns.Add("DbName", typeof(String));
    componentDbs.Rows.Add(new object[] { 123, 121, 12, null, "SecurableGuid", "Name", "Database name" });
    return componentDbs.Rows[0];
}

The rest of the code that is behind PersistComponentDb is

public int PersistComponentDb(ComponentDbModel componentDb)
{
    // Example implementation.
    return _repository.PersistComponentDb(componentDb);
}

and

int PersistComponentDb(ComponentDbModel componentDb);