[英]Can I do a text query with the mongodb c# driver
有沒有辦法將在 shell 查詢語法中表達的查詢提交給 mongo c# 驅動程序
例如像
Coll.find { "myrecs","$query : { x : 3, y : "abc" }, $orderby : { x : 1 } } ");
以 shell 指南為例
沒有您想要的完全相同的功能。
但是您可以從 json 創建 BsonDocument 進行查詢:
var jsonQuery = "{ x : 3, y : 'abc' }";
BsonDocument doc = MongoDB.Bson.Serialization
.BsonSerializer.Deserialize<BsonDocument>(jsonQuery);
之后,您可以從 BsonDocument 創建查詢:
var query = new QueryComplete(doc); // or probably Query.Wrap(doc);
您可以對排序表達式執行相同的操作:
var jsonOrder = "{ x : 1 }";
BsonDocument orderDoc = BsonSerializer.Deserialize<BsonDocument>(jsonQuery);
var sortExpr = new SortByWrapper(orderDoc);
您也可以像這樣為 MongoCollection 創建擴展方法:
public static List<T> GetItems<T>(this MongoCollection collection, string queryString, string orderString) where T : class
{
var queryDoc = BsonSerializer.Deserialize<BsonDocument>(queryString);
var orderDoc = BsonSerializer.Deserialize<BsonDocument>(orderString);
//as of version 1.8 you should use MongoDB.Driver.QueryDocument instead (thanks to @Erik Hunter)
var query = new QueryComplete(queryDoc);
var order = new SortByWrapper(orderDoc);
var cursor = collection.FindAs<T>(query);
cursor.SetSortOrder(order);
return cursor.ToList();
}
我沒有測試上面的代碼。 如果需要,以后會做。
更新:
剛剛測試了上面的代碼,它工作正常!
你可以像這樣使用它:
var server = MongoServer.Create("mongodb://localhost:27020");
var collection= server.GetDatabase("examples").GetCollection("SO");
var items = collection.GetItems<DocType>("{ x : 3, y : 'abc' }", "{ x : 1 }");
QueryComplete class 似乎已被棄用。 請改用MongoDB.Driver.QueryDocument
。 如下:
BsonDocument document = MongoDB.Bson.Serialization.BsonSerializer.Deserialize<BsonDocument>("{ name : value }");
QueryDocument queryDoc = new QueryDocument(document);
MongoCursor toReturn = collection.Find(queryDoc);
這是我編寫的 web 服務 function ,您可以發送過濾查詢、限制和跳過以進行分頁和排序查詢,以獲取您想要的任何集合。 它通用且快速。
/// <summary>
/// This method returns data from a collection specified by data type
/// </summary>
/// <param name="dataType"></param>
/// <param name="filter">filter is a json specified filter. one or more separated by commas. example: { "value":"23" } example: { "enabled":true, "startdate":"2015-10-10"}</param>
/// <param name="limit">limit and skip are for pagination, limit is the number of results per page</param>
/// <param name="skip">skip is is the page size * page. so limit of 100 should use skip 0,100,200,300,400, etc. which represent page 1,2,3,4,5, etc</param>
/// <param name="sort">specify which fields to sort and direction example: { "value":1 } for ascending, {"value:-1} for descending</param>
/// <returns></returns>
[WebMethod]
public string GetData(string dataType, string filter, int limit, int skip, string sort) {
//example: limit of 100 and skip of 0 returns the first 100 records
//get bsondocument from a collection dynamically identified by datatype
try {
MongoCollection<BsonDocument> col = MongoDb.GetConnection("qis").GetCollection<BsonDocument>(dataType);
if (col == null) {
return "Error: Collection Not Found";
}
MongoCursor cursor = null;
SortByWrapper sortExpr = null;
//calc sort order
try {
BsonDocument orderDoc = BsonSerializer.Deserialize<BsonDocument>(sort);
sortExpr = new SortByWrapper(orderDoc);
} catch { }
//create a query from the filter if one is specified
try {
if (filter != "") {
//sample filter: "{tags:'dog'},{enabled:true}"
BsonDocument query = BsonSerializer.Deserialize<BsonDocument>(filter);
QueryDocument queryDoc = new QueryDocument(query);
cursor = col.Find(queryDoc).SetSkip(skip).SetLimit(limit);
if (sortExpr != null) {
cursor.SetSortOrder(sortExpr);
}
return cursor.ToJson();
}
} catch{}
//if no filter specified or the filter failed just return all
cursor = col.FindAll().SetSkip(skip).SetLimit(limit);
if (sortExpr != null) {
cursor.SetSortOrder(sortExpr);
}
return cursor.ToJson();
} catch(Exception ex) {
return "Exception: " + ex.Message;
}
}
假設我在名為“mytest2”的集合中有這些記錄:
[{ "_id" : ObjectId("54ff7b1e5cc61604f0bc3016"), "timestamp" : "2015-01-10 10:10:10", "value" : "23" },
{ "_id" : ObjectId("54ff7b415cc61604f0bc3017"), "timestamp" : "2015-01-10 10:10:11", "value" : "24" },
{ "_id" : ObjectId("54ff7b485cc61604f0bc3018"), "timestamp" : "2015-01-10 10:10:12", "value" : "25" },
{ "_id" : ObjectId("54ff7b4f5cc61604f0bc3019"), "timestamp" : "2015-01-10 10:10:13", "value" : "26" }]
我可以使用以下參數進行 web 服務調用,以返回 100 條記錄,從第一頁開始,其中 value >= 23 且 value <= 26,按降序排列
dataType: mytest2
filter: { value: {$gte: 23}, value: {$lte: 26} }
limit: 100
skip: 0
sort: { "value": -1 }
享受!
以下是我用於從字符串和從 .NET 對象轉換為 BSON 查詢的一些例程(這是業務 object 包裝器的一部分,因此對該類有幾個參考):
public QueryDocument GetQueryFromString(string jsonQuery)
{
return new QueryDocument(BsonSerializer.Deserialize<BsonDocument>(jsonQuery));
}
public IEnumerable<T> QueryFromString<T>(string jsonQuery, string collectionName = null)
{
if (string.IsNullOrEmpty(collectionName))
collectionName = this.CollectionName;
var query = GetQueryFromString(jsonQuery);
var items = Database.GetCollection<T>(collectionName).Find(query);
return items as IEnumerable<T>;
}
public IEnumerable<T> QueryFromObject<T>(object queryObject, string collectionName = null)
{
if (string.IsNullOrEmpty(collectionName))
collectionName = this.CollectionName;
var query = new QueryDocument(queryObject.ToBsonDocument());
var items = Database.GetCollection<T>(collectionName).Find(query);
return items as IEnumerable<T>;
}
使用這些很容易通過字符串或 object 參數進行查詢:
var questionBus = new busQuestion();
var json = "{ QuestionText: /elimination/, GroupName: \"Elimination\" }";
var questions = questionBus.QueryFromString<Question>(json);
foreach(var question in questions) { ... }
或使用 object 語法:
var questionBus = new busQuestion();
var query = new {QuestionText = new BsonRegularExpression("/elimination/"),
GroupName = "Elimination"};
var questions = questionBus.QueryFromObject<Question>(query);
foreach(var question in questions) { ... }
我喜歡 object 語法只是因為用 C# 代碼寫出比處理 JSON 字符串中的嵌入引號要容易一些,如果它們是手工編碼的。
使用官方 C# 驅動程序,你會做這樣的事情:
var server = MongoServer.Create("mongodb://localhost:27017");
var db = server.GetDatabase("mydb");
var col = db.GetCollection("col");
var query = Query.And(Query.EQ("x", 3), Query.EQ("y", "abc"));
var resultsCursor = col.Find(query).SetSortOrder("x");
var results = resultsCursor.ToList();
來自 shell 的等效查詢將是:
col.find({ x: 3, y: "abc" }).sort({ x: 1 })
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.