java - 删除时外键的问题

Question

我有两个定义如下的表；从用户表中，hospitalId 和 poliklinikId 都引用表 relhospol，如果从 relhospol 中删除任何行(如果任何用户与之相关)，我想将 hospitalId 和 poliklinikId 设置为 null，DDL 这么说。当我从 SQLite 管理器中删除一行时，它会使用户的 hospitalId 和 PoliklinikId 为空，但是当我尝试从应用程序级别 (Java) 中删除一行时，它只会从 relhospol 中删除，它不会设置 null (hospitalId, PoliklinikId) 什么是缺失点？
JDBC驱动:SQLite-jdbc-3.7.2

CREATE TABLE [USER] (
  [ID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, 
  [GROUPID] INTEGER CONSTRAINT [FK_USER_GID] REFERENCES [GROUP]([ID]) ON DELETE SET NULL ON UPDATE CASCADE, 
  [HOSPITALID] INTEGER, 
  [POLIKLINIKID] INTEGER, 
  [NAME] VARCHAR(50) NOT NULL, 
  [LOGINID] VARCHAR(15) NOT NULL, 
  [EMAIL] VARCHAR(50) NOT NULL, 
  [PASSWORD] VARCHAR(32) NOT NULL, 
  CONSTRAINT [FK_USER_RELHOSPOL] FOREIGN KEY([HOSPITALID], [POLIKLINIKID]) REFERENCES [RELHOSPOL]([HOSPITALID], [POLIKLINIKID]) ON DELETE SET NULL ON UPDATE CASCADE);

CREATE UNIQUE INDEX [AS] ON [USER] ([LOGINID]);
CREATE UNIQUE INDEX [AS1] ON [USER] ([EMAIL]));

CREATE TABLE [RELHOSPOL] (
  [HOSPITALID] INTEGER CONSTRAINT [FK_RELHOSPOL_HOS] REFERENCES [HOSPITAL]([ID]) ON DELETE SET NULL ON UPDATE CASCADE, 
  [POLIKLINIKID] INTEGER CONSTRAINT [FK_RELHOSPOL_POL] REFERENCES [POLIKLINIK]([ID]) ON DELETE SET NULL ON UPDATE CASCADE, 
  CONSTRAINT [sqlite_autoindex_RELHOSPOL_1] PRIMARY KEY ([HOSPITALID], [POLIKLINIKID]));

Answer 1

您不能将主键设置为 NULL:

CREATE TABLE [RELHOSPOL] (
[HOSPITALID] INTEGER CONSTRAINT [FK_RELHOSPOL_HOS] REFERENCES [HOSPITAL]([ID]) ON DELETE SET NULL ON UPDATE CASCADE, 
[POLIKLINIKID] INTEGER CONSTRAINT [FK_RELHOSPOL_POL] REFERENCES [POLIKLINIK]([ID]) ON DELETE SET NULL ON UPDATE CASCADE, 
CONSTRAINT [sqlite_autoindex_RELHOSPOL_1] PRIMARY KEY ([HOSPITALID], [POLIKLINIKID]));

您正试图从哪个表中删除一行？你能发布 DELETE SQL 吗？