《mongodb 小操作》要點:
本文介紹了mongodb 小操作,希望對您有用。如果有疑問,可以聯系我們。
相關主題:非關系型數據庫
mongodb-driver.jar操作數據庫
collection是DBCollection對象
添加數據
collection.save(new BasicDBObject("author", "yinjihuan").append("title", "mongodb"));
編輯數據
collection.update(new BasicDBObject("author", "yinjihuan"),
new BasicDBObject("$set", new BasicDBObject("title", "mongodb3.0")));
刪除數據
collection.remove(new BasicDBObject("author", "yinjihuan"));
查詢所有數量
long count = collection.count();
查詢所有數據
DBCursor cursor = collection.find();
while (cursor.hasNext()) {
DBObject data = cursor.next();
System.out.println(data.toString());
}
查詢第一條數據
DBObject data = collection.findOne();
帶條件查詢
DBObject query = new BasicDBObject("author", "yinjihuan");
cursor = collection.find(query);
大于(gt)查詢
query = new BasicDBObject("visit_count", new BasicDBObject("$gt", 10));
cursor = collection.find(query);
小于(lt)查詢
query = new BasicDBObject("visit_count", new BasicDBObject("$lt", 10));
cursor = collection.find(query);
查詢固定的列
query = new BasicDBObject("author", "yinjihuan");
DBObject fields = new BasicDBObject("author", 1);
cursor = collection.find(query, fields);
分頁查詢,當數據量較大的時候不建議使用skip,會很慢的
建議按id排序,每查詢一頁記住最后一條id,然后大于id在limit
query = new BasicDBObject("author", "yinjihuan");
cursor = collection.find(query, fields).skip(0).limit(10);
創建索引
collection.createIndex(new BasicDBObject("author_idx", 1));
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