如何在indexdb for browsers中使用类似where子句的条件
如何在indexdb for browsers中使用类似where子句的条件
提问于 2015-05-17 22:50:18
我使用的是indexdb，因为它支持所有浏览器。我已经成功地添加了数据并从indexdb获得了数据，但我想使用where子句条件。比如我有产品名称，病原体，疾病，路线，所以我想要获取产品名称是Ali，疾病是皮肤的数据。它们是我从不同的站点得到的，它用两个输入域中提供的值开始和结束来显示所有的记录。
这是我正在使用的代码。
<!doctype html>
<html>
<head>
</head>
<body>
<script>
var db;
function indexedDBOk() {
return "indexedDB" in window;
}
document.addEventListener("DOMContentLoaded", function() {
//No support? Go in the corner and pout.
if(!indexedDBOk) return;
var openRequest = indexedDB.open("products",1);
//var openRequest = indexedDB.open("idarticle_people5",1);
openRequest.onupgradeneeded = function(e) {
var thisDB = e.target.result;
if(!thisDB.objectStoreNames.contains("products")) {
var os = thisDB.createObjectStore("products", {autoIncrement:true});
//I want to get by name later
os.createIndex("name", "name", {unique:false});
//I want email to be unique
os.createIndex("pathogen", "pathogen", {unique:false});
os.createIndex("disease", "disease", {unique:false});
os.createIndex("route", "route", {unique:false});
}
}
openRequest.onsuccess = function(e) {
db = e.target.result;
//Listen for add clicks
document.querySelector("#addButton").addEventListener("click", addPerson, false);
//Listen for get clicks
document.querySelector("#getButton").addEventListener("click", getPerson, false);
}
openRequest.onerror = function(e) {
//Do something for the error
}
},false);
function addPerson(e) {
var name = document.querySelector("#name").value;
var pathogen = document.querySelector("#pathogen").value;
var disease = document.querySelector("#disease").value;
var route = document.querySelector("#route").value;
console.log("About to add "+name+"/"+pathogen);
//Get a transaction
//default for OS list is all, default for type is read
var transaction = db.transaction(["products"],"readwrite");
//Ask for the objectStore
var store = transaction.objectStore("products");
//Define a person
var person = {
name:name,
pathogen:pathogen,
disease:disease,
route:route
}
//Perform the add
var request = store.add(person);
request.onerror = function(e) {
alert("Sorry, that email address already exists.");
console.log("Error",e.target.error.name);
console.dir(e.target);
//some type of error handler
}
request.onsuccess = function(e) {
console.log("Woot! Did it");
}
}
function getPerson(e) {.value名称= var (“#nameSearch”)var；
var endname = document.querySelector("#diseaseSearch").value;
if(name == "" && endname == "") return;
var transaction = db.transaction(["products"],"readonly");
var store = transaction.objectStore("products");
var index = store.index("name");
//Make the range depending on what type we are doing
var range;
if(name != "" && endname != "") {
range = IDBKeyRange.bound(name, endname);
} else if(name == "") {
range = IDBKeyRange.upperBound(endname);
} else {
range = IDBKeyRange.lowerBound(name);
}
var s = "";
index.openCursor(range).onsuccess = function(e) {
var cursor = e.target.result;
if(cursor) {
s += "<h2>Key "+cursor.key+"</h2><p>";
for(var field in cursor.value) {
s+= field+"="+cursor.value[field]+"<br/>";
}
s+="</p>";
cursor.continue();
}
document.querySelector("#status").innerHTML = s;
}
}
</script>
<input type="text" id="name" placeholder="Name"><br/>
<input type="text" id="pathogen" placeholder="Pathogen"><br/>
<input type="text" id="disease" placeholder="Disease"><br/>
<input type="text" id="route" placeholder="Route"><br/>
<button id="addButton">Add Data</button>
<p/>
<input type="text" id="nameSearch" placeholder="Name"><br/>
<input type="text" id="diseaseSearch" placeholder="Disease"><br/>
<button id="getButton">Get By Name</button>
<p/>
<div id="status"></div>
</body>
</html>回答 2
Stack Overflow用户
发布于 2015-05-18 19:10:09
您可以使用三个参数尝试以下步骤：
- databaseid
- tableid -存储名称
- 回调函数，返回所选data
- 条件函数数组。对于ok记录返回true，对于其他记录返回false。
代码如下：
function selectFromTable (databaseid, tableid, cb, cond) {
var request = window.indexedDB.open(databaseid);
request.onsuccess = function(event) {
var res = [];
var ixdb = event.target.result;
var tx = ixdb.transaction([tableid]);
var store = tx.objectStore(tableid);
var cur = store.openCursor();
cur.onblocked = function(event) {
}
cur.onerror = function(event) {
}
cur.onsuccess = function(event) {
var cursor = event.target.result;
if(cursor) {
if(cond(cursor.value) ) res.push(cursor.value);
cursor.continue();
} else {
ixdb.close();
cb(res);
}
}
} Stack Overflow用户
发布于 2015-05-27 02:21:26
尝试使用browser database API adapter并从its wiki page阅读有关其用法的信息。您需要包含所有3个JS文件才能开始。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/30288133
复制相关文章
相似问题
腾讯云开发者
Copyright © 2013 - 2026 Tencent Cloud. All Rights Reserved. 腾讯云 版权所有
深圳市腾讯计算机系统有限公司 ICP备案/许可证号：粤B2-20090059 
粤公网安备44030502008569号
腾讯云计算（北京）有限责任公司 京ICP证150476号 | 京ICP备11018762号