SQLite語法REPLACE + WHERE

Question

我在做下面的代碼錯了嗎？

CREATE TABLE IF NOT EXISTS chunks(x Integer(20) NOT NULL, y Integer(20) NOT NULL, 
      height Integer(20) NOT NULL, version Timestamp default (strftime('%s', CURRENT_TIME)), 
      datas Text NOT NULL); 
REPLACE INTO chunks VALUES(0,0,0,NULL,'Bla') WHERE x IS 0 AND y IS 0 AND height IS 0; 

Answer 1

更換要求表，對你要搜索的列的唯一約束，始終刪除舊行，如果它發現之一。

一個更好的想法是明確檢查該行是否存在：

cursor.execute("UPDATE chunks SET ... WHERE x = ? AND y = ? AND height = ?", 
       [0, 0, 0]) 
if cursor.rowcount == 0: 
    cursor.execute("INSERT INTO chunks ...")