加預設值為何把舊紀錄都標成 New？

先核來源與已訂規則

本例舊 A 沒類別依據，加 category DEFAULT New 卻令現有行出現 New。搬移應先加可空欄，只按所附歷史依據補值；舊紀錄未曾證實屬 New。

已填假設輸入
紀錄	輸入 JSON
原例輸入	{"records":[{"id":1,"name":"A"}],"evidence":[]}

下載可編輯 CSV ↓

比較兩條實際路徑

更正 A 的 category 仍 null。差異來自實際 ALTER 及回讀，不是匯入程序代作新類別決定。

錯誤與更正路徑的輸出
路徑	輸出 JSON
錯誤路徑	[{"id":1,"name":"A","category":"New"}]
更正路徑	[{"id":1,"name":"A","category":null}]

下載可編輯 CSV ↓

本地 Node.js 程序：22.23.3 或 24.14.1

import {DatabaseSync} from 'node:sqlite';
import {TextDecoder} from 'node:util';
import {inflateSync} from 'node:zlib';
import {posix} from 'node:path';
import {createHash} from 'node:crypto';
const rows=(db,sql)=>db.prepare(sql).all().map(r=>({...r}));
const failed=(action)=>{try{action();return null;}catch(e){return {code:e.errcode??e.code??e.name};}};

import assert from 'node:assert/strict';
const run=function run(i,corrected=true){
    const db=new DatabaseSync(':memory:');try{db.exec('CREATE TABLE target(id INTEGER PRIMARY KEY,name TEXT);');
      for(const r of i.records)db.prepare('INSERT INTO target VALUES(?,?)').run(r.id,r.name);
      db.exec(corrected?'ALTER TABLE target ADD COLUMN category TEXT':"ALTER TABLE target ADD COLUMN category TEXT DEFAULT 'New'");
      if(corrected)for(const e of i.evidence)db.prepare('UPDATE target SET category=? WHERE id=?').run(e.category,e.id);
      return rows(db,'SELECT * FROM target ORDER BY id');
    }finally{db.close();}
  };
const cases=[{"label":"misleading base","input":{"records":[{"id":1,"name":"A"}],"evidence":[]},"expected":[{"id":1,"name":"A","category":"New"}],"corrected":false},{"label":"corrected base","input":{"records":[{"id":1,"name":"A"}],"evidence":[]},"expected":[{"id":1,"name":"A","category":null}],"corrected":true},{"label":"evidenced historical category","input":{"records":[{"id":1,"name":"A"}],"evidence":[{"id":1,"category":"Old"}]},"expected":[{"id":1,"name":"A","category":"Old"}],"corrected":true},{"label":"no historical rows","input":{"records":[],"evidence":[]},"expected":[],"corrected":true}];
for(const test of cases){
  const actual=run(test.input,test.corrected);
  assert.deepEqual(actual,test.expected,test.label);
  console.log(test.label,actual);
}

下載可執行例子 ↓

下次載入前核邊界

依據明訂 Old 就填 Old；舊表沒有紀錄則照空。

可編輯邊界紀錄及預期輸出
情況	輸入 JSON	預期輸出 JSON
明確歷史類別依據	{"records":[{"id":1,"name":"A"}],"evidence":[{"id":1,"category":"Old"}]}	[{"id":1,"name":"A","category":"Old"}]
沒有舊紀錄	{"records":[],"evidence":[]}	[]

下載可編輯 CSV ↓

新加預設值可否確立舊紀錄歷史類別？

查看參考答案

不可，此處 A 仍未知。只有對應歷史依據已列 Old，才補 Old。

先核來源與已訂規則

比較兩條實際路徑

下次載入前核邊界

相關資源