<!DOCTYPE HTML PUBLIC
"-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd"
>
<
html
>
<
head
>
<
meta
http-equiv=
"Content-Type"
content=
"text/html; charset=utf-8"
>
<
title
>游标与index和游标结合
</
title
>
<
script
>
var
myDB={
name:
"helloindexDB",
version:
1,
db:
null
}
function
openDB(
name,
version){
var
version =
version ||
1;
var
request=
widow.
indexedDB.
open(
name,
version);
request.
onerror=
function(
e){
}
request.
onsuccess=
function(
e){
myDB.
db=
e.
target.
result;
}
//以下是 对 数据表 进行操作
request.
onupgradeneeded=
function(
e){
var
db=
e.
target.
result;
//如果没有 student 表
if(!
db.
objectStoreNames.
contains(
"students"))
{
//创建student表，并设置id为key
var
story=
db.
createObjectStore(
"students",{
keyPath:
"id"});
//创建字段
story.
createIndex(
"nameIndex",
"name",{
unique:
true} );
story.
createIndex(
"ageIndex",
"age",{
unique:
false});
}
}
}
var
students=
[
{
id:
101，
name:
"aa",
age:
10
},
{
id:
102，
name:
"bb",
age:
11
},
{
id:
103，
name:
"cc",
age:
12
}
]
function
addData(
db,
storeName){
var
transaction=
db.
transaction(
storeName,
"readwrite");
//读取权限
var
store=
transaction.
objectStore(
storeName);
for(
var
i=
0;
i<
students.
length;
i++)
{
store.
add(
students[
i]);
}
}
//执行操作
openDB(
myDB.
name,
myDB.
version);
setTimeout(
function(){
addData(
myDB.
db,
"students");
},
1000);
//以上是上一节内容
//通过 姓名 来获取数据
function
getDataByIndexName(
db,
storeName){
var
transaction=
db.
transaction(
storeName);
//通过链接来获取数据表（数据仓库）
var
store=
transaction.
objectStore(
storeName);
//实例化数据表
var
index=
store.
index(
"nameIndex");
//获取索引
index.
get(
"aa").
onsuccess=
function(
e){
var
student=
e.
target.
result;
console.
log(
student.
name+
"--"+
student.
age+
"--"+
student.
id);
}
}
//执行 getDataByIndexName
setTimeout(
function(){
getDataByIndexName(
myDB.
db,
"students");
},
1000)
//通过 年龄 来获取数据
function
getDataByIndexAge(
db,
storeName){
var
transaction=
db.
transaction(
storeName);
//通过链接来获取数据表（数据仓库）
var
store=
transaction.
objectStore(
storeName);
var
index=
store.
index(
"ageIndex");
index.
get(
11).
onsuccess=
function(
e){
var
student=
e.
target.
result;
console.
log(
"姓名："+
student.
name+
"--年龄："+
student.
age+
"--id："+
student.
id);
}
}
//执行 getDataByIndexAge
setTimeout(
function(){
getDataByIndexAge(
myDB.
db,
"students");
},
1000)
// {#
// 综上所述：通过name来获取的数据是可以获得相同name的数据，但是age不行。因为name是唯一的，
// age不是唯一的 ，
// 所以 要用 “游标” 来解决
// #}
//以上是上一节的内容
//游标的使用
function
fetchStoryByCursor(
db,
storeName){
var
transaction=
db.
transaction(
storeName);
var
store=
transaction.
objectStore(
storeName);
var
request=
store.
openCursor();
//打开游标
request.
onsuccess=
function(
e){
var
cursor=
e.
target.
result;
if(
cursor)
//如果 可以 使用 “游标”
{
console.
log(
cursor.
key);
var
currentStudent=
cursor.
value;
console.
log(
currentStudent.
name);
cursor.
continue();
//使游标下移 如果没有 就 返回 undifined
}
}
}
setTimeout(
function(){
fetchStoryByCursor(
myDB.
db,
"students");
},
1000)
//index与游标结合
function
getData(
db,
storeName){
var
transaction=
db.
transaction(
storeName);
var
store=
db.
objectStore(
storeName);
var
index=
store.
index(
"ageIndex");
var
request=
index.
openCursor(
IDBKeyRange.
only(
11));
request.
onsuccess=
function(
e){
var
cursor=
e.
target.
result;
if(
cursor){
var
student=
cursor.
value;
console.
log(
student.
id);
cursor.
continue();
}
}
}
setTimeout(
function(){
getData(
myDB.
db,
"students");
},
1000)
//openCursor范围
function
getDatafanwei(
db,
storeName){
var
transaction=
db.
transaction(
storeName);
var
store=
db.
objectStore(
storeName);
var
index=
store.
index(
"nameIndex");
//IDBKeyRange.only(value) 只获取指定的数据
//IDBKeyRange.lowerbound(value,isOpen) 第一个获取最小值是value，第二个参数是指 是否排除value本身
//IDBKeyRange.upperbound(value,isOpen) 第一个获取最大值是value，第二个参数是指 是否排除value本身
//IDBKeyRange.bound(value1,value2,isOpen1,isOpen2)
//var request=index.openCursor(IDBKeyRange.only(11));
var
request=
index.
openCursor(
IDBKeyRange.
bound(
"b",
"z",
false,
true));
request.
onsuccess=
function(
e){
var
cursor=
e.
target.
result;
if(
cursor){
var
student=
cursor.
value;
console.
log(
student.
id);
cursor.
continue();
}
}
}
setTimeout(
function(){
getDatafanwei(
myDB.
db,
"students");
},
1000)
</
script
>
</
head
>
<
body
>
</
body
>
</
html
>