資料庫是屬於伺服器的，這是天經地義的事，但是有時候資料也許並非需要儲存在伺服器，但是這些資料也是一條一條的記錄，怎麼辦？今天來帶領你來領略H5的一個新特性--indexedDB的風騷。你會情不自禁的發出感嘆--不可思議！
indexedDB沒有建立資料庫的概念，你可以直接連結資料庫，如果你連結的資料庫不存在，那麼會自動的建立一個資料庫。看下面的這個例子。
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Document</title></head><body><button type="" id='conbtn'>链接数据库</button><script>// In the following line, you should include the prefixes of implementations you want to test. window.indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB; // DON'T use "var indexedDB = ..." if you're not in a function.
// Moreover, you may need references to some window.IDB* objects: window.IDBTransaction = window.IDBTransaction || window.webkitIDBTransaction || window.msIDBTransaction;
window.IDBKeyRange = window.IDBKeyRange || window.webkitIDBKeyRange || window.msIDBKeyRange // (Mozilla has never prefixed these objects, so we don't need window.mozIDB*)
function connectDB(name,version,success,error){
let dbConnect = indexedDB.open(name,version);
dbConnect.onsuccess = function(e){
console.log('数据库链接成功！');
success(e.target.result);
}
dbConnect.onerror = function(e){
console.log('数据库链接失败！');
error(e);
}
dbConnect.onupgradeneeded = function(e){
success(e.target.result);
let oldVersion = e.oldVersion;
let newVersion = e.newVersion;
console.log('数据库更新成功，旧的版本号为：'+oldVersion+",新的版本号为："+newVersion);
}
}
window.onload=function(){
let btn = document.getElementById('conbtn');
btn.onclick = function(){
connectDB('haha',1,function(){
console.log('链接成功，或者更新成功回调函数');
},function(){
console.log('链接失败回调函数！')
});
}
}</script></body></html>我點了兩次連結資料庫，結果是這樣的。
在Application的indexedDB中我們發現多了一個東西。
可以看到haha資料庫已經成功建立了。
indexedDB的open方法用來連結或更新資料庫，第一次建立也認為是一次更新。第一個參數是資料庫的名字，第二個參數為版本號。第一次建立或版本號改變時出發更新事件upgradeneeded，連結成功後出發success事件，連結出錯時觸發error事件。
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Document</title></head><body><button type="" id='conbtn'>链接数据库</button><script>// In the following line, you should include the prefixes of implementations you want to test. window.indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB; // DON'T use "var indexedDB = ..." if you're not in a function.
// Moreover, you may need references to some window.IDB* objects: window.IDBTransaction = window.IDBTransaction || window.webkitIDBTransaction || window.msIDBTransaction;
window.IDBKeyRange = window.IDBKeyRange || window.webkitIDBKeyRange || window.msIDBKeyRange // (Mozilla has never prefixed these objects, so we don't need window.mozIDB*)
function connectDB(name,version,success,update,error){
let dbConnect = indexedDB.open(name,version);
dbConnect.onsuccess = function(e){
console.log('数据库链接成功！');
success(e.target.result);
}
dbConnect.onerror = function(e){
console.log('数据库链接失败！');
error(e);
}
dbConnect.onupgradeneeded = function(e){
update(e.target.result);
let oldVersion = e.oldVersion;
let newVersion = e.newVersion;
console.log('数据库更新成功，旧的版本号为：'+oldVersion+",新的版本号为："+newVersion);
}
} function createTable(idb,storeName,key,idxs){if(!idb){
console.log(idb);return ;
}if(!key || !idxs){
console.log('参数错误');return ;
}if(!storeName){
console.log('storeName必须');return ;
}try{var store = idb.createObjectStore(storeName,key);
console.log('数据库存储对象(table)创建成功');for(var i = 0;i<idxs.length;i++){var idx = idxs[i];
store.createIndex(idx.indexName,idx.keyPath,idx.optionalParameters);
console.log('索引'+idx.indexName+'创建成功');
}
}catch(e){
console.log('建表出现错误');
console.log(JSON.stringify(e))
}
}
window.onload=function(){
let btn = document.getElementById('conbtn');
btn.onclick = function(){
connectDB('haha',1, function(idb){
console.log('链接成功，或者更新成功回调函数');
},function(idb){ createTable(idb,'test',{keyPath:'id',autoIncrement:true},[
{
indexName:'testIndex',
keyPath:'name',
optionalParameters:{
unique:true,
multiEntry:false }}]);
},function(){
console.log('链接失败回调函数！')
});
}
}</script></body></html>
我點了一下按鈕結果時這樣的。
這裡用到的兩個核心方法時createObjectStore，和createIndex,這兩個方法必須在資料庫發生更新的事件中執行。
createObjectStore方法可以理解成是創建表，接受第一個參數為一個字串，表示表名，第二個參數是一個對象，指定主鍵相關的東西，{keyPath:'主鍵是哪個字段',autoIncrement:是否自增}。
createIndex方法是建立索引的，接受三個參數，第一個是字串，表示索引的名字，第二個參數表示欄位名稱（誰的索引），第三個參數是個對象，具體自己查去。索引的作用是在查詢操作時可以用到，不詳講，自行google吧。
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Document</title></head><body><button type="" id='conbtn'>链接数据库</button><button type="" id='add'>添加数据</button><script>// In the following line, you should include the prefixes of implementations you want to test. window.indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB; // DON'T use "var indexedDB = ..." if you're not in a function.
// Moreover, you may need references to some window.IDB* objects: window.IDBTransaction = window.IDBTransaction || window.webkitIDBTransaction || window.msIDBTransaction;
window.IDBKeyRange = window.IDBKeyRange || window.webkitIDBKeyRange || window.msIDBKeyRange // (Mozilla has never prefixed these objects, so we don't need window.mozIDB*)
function connectDB(name,version,success,update,error){
let dbConnect = indexedDB.open(name,version);
dbConnect.onsuccess = function(e){
console.log('数据库链接成功！');
success(e.target.result);
}
dbConnect.onerror = function(e){
console.log('数据库链接失败！');
error(e);
}
dbConnect.onupgradeneeded = function(e){
update(e.target.result);
let oldVersion = e.oldVersion;
let newVersion = e.newVersion;
console.log('数据库更新成功，旧的版本号为：'+oldVersion+",新的版本号为："+newVersion);
}
} function createTable(idb,storeName,key,idxs){if(!idb){
console.log(idb);return ;
}if(!key || !idxs){
console.log('参数错误');return ;
}if(!storeName){
console.log('storeName必须');return ;
}try{var store = idb.createObjectStore(storeName,key);
console.log('数据库存储对象(table)创建成功');for(var i = 0;i<idxs.length;i++){var idx = idxs[i];
store.createIndex(idx.indexName,idx.keyPath,idx.optionalParameters);
console.log('索引'+idx.indexName+'创建成功');
}
}catch(e){
console.log('建表出现错误');
console.log(JSON.stringify(e))
}
}function add(storeName,values){
connectDB('haha',1,function(idb){var ts = idb.transaction(storeName,"readwrite");var store = ts.objectStore(storeName); for(var i = 0;i<values.length;i++){
(function(i){var value = values[i];var req = store.put(value);
req.onsuccess = function(){
console.log("添加第"+i+"个数据成功");
}
req.onerror = function(e){
console.log("添加第"+i+"个数据失败");
console.log(JSON.stringify(e));
}
})(i)
}
ts.oncomplete = function(){
console.log('添加数据事务结束！');
}
},function(){},function(){});
}
window.onload=function(){
let btn = document.getElementById('conbtn');
btn.onclick = function(){
connectDB('haha',1, function(idb){
console.log('链接成功，或者更新成功回调函数');
},function(idb){
createTable(idb,'test',{keyPath:'id',autoIncrement:true},[
{
indexName:'testIndex',
keyPath:'name',
optionalParameters:{
unique:true,
multiEntry:false }}]);
},function(){
console.log('链接失败回调函数！')
});
}
let add1 = document.getElementById('add');
add1.onclick = function(){
add('test',[{name:"fjidfji",a:'uuuu'}])
}
}</script></body></html>
Document链接数据库添加数据查询
# 查詢操作主要用到了遊標，這個說起來還比較多，沒時間說了，自行google。還有很多的操作這裡不講了。給一個我封裝的不是很好的簡易庫，僅供參考。
一個簡易函式庫。 ###
(function(window){'use strict';
window.dbUtil={
indexedDB :(window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB),
IDBTransaction :(window.IDBTransaction || window.webkitIDBTransaction || window.msIDBTransaction),
IDBKeyRange :(window.IDBKeyRange || window.webkitIDBKeyRange || window.msIDBKeyRange),
IDBCursor : (window.IDBCursor || window.webkitIDBCursor || window.msIDBCursor),
idb:null,
dbName:"",
dbVersion:"",/**
* 初始化数据库，创建表和建立链接
* @param {[type]} dbName [description]
* @param {[type]} dbVersion [description]
* @param {[type]} storeObjs [description]
* @return {[type]} [description] */initDB:function (dbName,dbVersion,storeObjs){this.dbName = dbName;this.dbVersion = dbVersion;var dbConnect = this.indexedDB.open(this.dbName,this.dbVersion);var self = this;
dbConnect.onsuccess = function(e){
self.idb = e.target.result;
self.log('数据库链接成功！');
}
dbConnect.onerror = function(e){
console.log(e)
self.log('数据库链接失败!');
}
dbConnect.onupgradeneeded = function(e){
self.idb = e.target.result;var ts = e.target.transaction;var oldVersion = e.oldVersion;var newVersion = e.newVersion;
self.log('数据库更新成功，旧的版本号为：'+oldVersion+",新的版本号为："+newVersion);if(storeObjs){for(var k = 0,len=storeObjs.length;k<len;k++){var storeObj = storeObjs[k];var storeName = storeObj.storeName;var key = storeObj.key;var idxs = storeObj.idxs;
self.createTable(storeName,key,idxs)
}
}
}
},/**
* 创建数据库存储对象（表）
* @param {[type]} key [description]
* @param {[type]} [description]
* @return {[type]} [description] */createTable:function(storeName,key,idxs){var self = this;var idb = self.idb;if(!idb){
self.log('数据库没有链接');return ;
}if(!key || !idxs){
self.log('参数错误');return ;
}if(!storeName){
self.log('storeName必须');return ;
}try{var store = idb.createObjectStore(storeName,key);
self.log('数据库存储对象(table)创建成功');for(var i = 0;i<idxs.length;i++){var idx = idxs[i];
store.createIndex(idx.indexName,idx.keyPath,idx.optionalParameters);
self.log('索引'+idx.indexName+'创建成功');
}
}catch(e){
self.log('建表出现错误');
console.log(JSON.stringify(e))
}
},/**
* [add description]
* @param {[type]} storeName [description]
* @param {[type]} values [description] */add:function(storeName,values){var dbConnect = this.indexedDB.open(this.dbName,this.dbVersion);var self = this;
dbConnect.onsuccess = function(e){var idb = e.target.result;var ts = idb.transaction(storeName,"readwrite");var store = ts.objectStore(storeName);for(var i = 0;i<values.length;i++){
(function(i){var value = values[i];var req = store.put(value);
req.onsuccess = function(){
self.log("添加第"+i+"个数据成功");
}
req.onerror = function(e){
self.log("添加第"+i+"个数据失败");
self.log(JSON.stringify(e));
}
})(i)
}
ts.oncomplete = function(){
self.log('添加数据事务结束！');
}
}
},/**
* [select description]
* @param {[type]} storeName [description]
* @param {[type]} count [description]
* @param {Function} callback [description]
* @param {[type]} indexName [description]
* @return {[type]} [description] */select:function(storeName,count,callback,indexName){var dbConnect = this.indexedDB.open(this.dbName,this.dbVersion);var self = this;var total = 0;var data = [];
dbConnect.onsuccess = function(e){
self.log("数据库链接成功！");var idb = e.target.result;var ts = idb.transaction(storeName,"readonly");var store = ts.objectStore(storeName);var req = store.count();var req2 = null;
req.onsuccess = function(){
total = this.result;var realCount = (count<=total)?count:total;if(typeof indexName == 'undefined'){var range = IDBKeyRange.bound(0,"9999999999999999999999");
req2 = store.openCursor(range,'prev');var cc = 0;
req2.onsuccess = function(){var cursor = this.result;if(total == 0){
callback([]);return;
}if(cursor){
cc++;
data.push(cursor.value);if(cc==realCount){
callback(data);return;
}
cursor.continue();
}
}
req2.onerror = function(){
self.log("检索出错")
}
}else{//待写 }
}
}
},/**
* [delete description]
* @param {[type]} storeName [description]
* @param {[type]} key [description]
* @return {[type]} [description] */delete:function(storeName,key,callback){var dbConnect = this.indexedDB.open(this.dbName,this.dbVersion);
let self = this;
dbConnect.onsuccess = function(e){var idb = e.target.result;var ts = idb.transaction(storeName,'readwrite');var store = ts.objectStore(storeName);
store.delete(key);
self.log('删除成功！');if(callback){
callback();
}
}
},/**
* [funciton description]
* @param {[type]} storeName [description]
* @param {[type]} key [description]
* @param {[type]} existCall [description]
* @param {[type]} notExistCall [description]
* @return {[type]} [description] */isExist:function(storeName,key,existCall,notExistCall){var dbConnect = this.indexedDB.open(this.dbName,this.dbVersion);
dbConnect.onsuccess = function(e){var idb = e.target.result;var ts = idb.transaction(storeName,'readonly');var store = ts.objectStore(storeName);var req = store.get(key);
req.onsuccess = function(){if(this.result == undefined){
notExistCall();
}else{
existCall(this.result);
}
}
req.onerror = function(){
notExistCall();
}
}
},/**
* clear
* @param {[type]} storeName [description]
* @return {[type]} [description] */clear:function clearObjectStore(storeName){var dbConnect = this.indexedDB.open(this.dbName,this.dbVersion);
dbConnect.onsuccess = function(e){var idb = e.target.result;var ts = idb.transaction(storeName,'readwrite');var store = ts.objectStore(storeName);
store.clear();
}
},/**
* 删除数据库
* @param {[type]} dbName [description]
* @return {[type]} [description] */dropDatabase:function(dbName){this.indexedDB.deleteDatabase(dbName);this.log('成功删除数据库:'+dbName);
},/**
* [log description]
* @param {[type]} msg [description]
* @return {[type]} [description] */log:function(msg){
console.log((new Date()).toTimeString()+":"+msg)
}
}
})(window);以上是將資料庫從伺服器移到瀏覽器--indexedDB基本操作封裝的詳細內容。更多資訊請關注PHP中文網其他相關文章！
