CREATE TABLE DocBarCode (
  DocBarCodeID INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
  DocID INTEGER NOT NULL CONSTRAINT [FK_DocBarCode_DocID] REFERENCES [Doc]([DocID]) ON DELETE RESTRICT ON UPDATE RESTRICT DEFERRABLE
);

SELECT * 
FROM Doc, DocBarCode 
WHERE Doc.DocID=DocBarCode.DocID // <-- ТУТ

CREATE INDEX [IDX_DocID] ON [DocBarCode] ([DocID]);