public static bool JsonContained(this DbFunctions _, object contained, object json);
public static bool JsonContains(this DbFunctions _, object json, object contained);
public static bool JsonExistAll(this DbFunctions _, object json, params string[] keys);
public static bool JsonExistAny(this DbFunctions _, object json, params string[] keys);
public static bool JsonExists(this DbFunctions _, object json, string key);
public static string JsonTypeof(this DbFunctions _, object json);