| 摘要 |
PURPOSE:To prevent the destruction of a data base due to a wrong combination by checking the interchangeability between the data base and a data base control system through said control system with reference to the level number of the data base and the contents of an interchangeability check table. CONSTITUTION:When the interchangeability check processing is carried out by a data base control system, the level number N of the data base is checked for a function (f) to be executed when the data base is opened. Then the control system retrieves an interchangeability check table of its own and checks whether or not the number N is smaller than the upper limit Nb of level number interchangeability owned by the system itself for the function (f). When the result YES is obtained, it is also checked whether or not the number N is larger than the lower limit Na of level number interchangeability. If the result YES is obtained, it is decided that the data base is normal. While an error is decided if no result YES is obtained. When the number N is larger than the number Nb, it is checked whether or not the number N is larger than the number Na for the function (f) at the own semi-sequence part. When the result YES is obtained, an access is permitted to the data base. While an error is decided if no result YES is obtained. |
