mongo 批量轉換欄位型別的方法
引：由於專案前期開發的人沒規劃好，導致功能上業務邏輯的阻塞，現記錄下mongo如何批量轉換資料型別
函式解析
1.要先查詢出需要修改的欄位型別，不然直接轉換，如果資料表比較混亂，會導致轉換報錯
2.print 可以在mongo shell中 輸出引數
$type 有效的型別值，如下：
| Type | Number | Alias | Notes |
|---|---|---|---|
| Double | 1 | “double” | |
| String | 2 | “string” | |
| Object | 3 | “object” | |
| Array | 4 | “array” | |
| Binary data | 5 | “binData” | |
| Undefined | 6 | “undefined” | Deprecated. |
| ObjectId | 7 | “objectId” | |
| Boolean | 8 | “bool” | |
| Date | 9 | “date” | |
| Null | 10 | “null” | |
| Regular Expression | 11 | “regex” | |
| DBPointer | 12 | “dbPointer” | Deprecated. |
| JavaScript | 13 | “javascript” | |
| Symbol | 14 | “symbol” | Deprecated. |
| JavaScript (with scope) | 15 | “javascriptWithScope” | |
| 32-bit integer | 16 | “int” | |
| Timestamp | 17 | “timestamp” | |
| 64-bit integer | 18 | “long” | |
| Decimal128 | 19 | “decimal” | New in version 3.4. |
| Min key | -1 | “minKey” | |
| Max key | 127 | “maxKey” |
好了，接下來進行轉換的一步
//string轉為double型別
db.order.find({userID:{$type:"string"}}).forEach( function (x) {
print( "user: " + x.userID )；
x.userID = parseInt(x.userID);
db.order.save(x);
});
//string轉為int型別
db.order.find({userID:{$type:"string"}}).forEach( function (x) {
print( "user: " + x.userID )；
x.userID = NumberInt(x.userID);
db.order.save(x);
});
//string轉化為date型別
db.order.find({userID:{$type:"string"}}).forEach( function (x) {
print( "user: " + x.userID )；
x.userID = new ISODate(x.userID);
db.order.save(x);
});
//string轉化為obj型別
db.order.find({userID:{$type:"string"}}).forEach( function (x) {
print( "user: " + x.userID )；
x.userID = ObjectId(x.userID);
db.order.save(x);
});
type 型別 - 官網參考： https://docs.mongodb.com/manual/reference/operator/query/type/index.html