blocks|key|469756|text|我相信有很多方法可以做到这一点(而且有很多方法比我的方法更好)，但我处理这些问题的方法如下：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|469757|首先，我在应用程序的第一个.h文件(将首先加载的文件)中定义一个常量来表示首次加载，并将其设置为0：|469758|#define+FirstTime+0|code-block|syntax|javascript|469759|现在您必须知道，我打算将这个常量的值保存在Documents文件夹中以备将来参考，因此我使用了一个共享数据实例。在viewDidLoad中，我执行以下测试：|offset|length|style|CODE|469760|//if+first+time+run+of+this+version
if(+[MyDataModel+sharedInstance].count+<+(FirstTime+%2B+1)+)
{
++++//do+what+you+need+to+do+as+the+first+time+load+for+this+version

++++[MyDataModel+sharedInstance].count%2B%2B
++++//save+the+count+value+to+disk+so+on+next+run+you+are+not+first+time
++++//this+means+count+=+1
}|469761|现在诀窍是在你的新应用程序版本(比如1.1)上。我将FirstTime更改为2：|469762|#define+FirstTime+2|469763|由于磁盘上保存的第一时间值是1，这意味着您将被上面的if语句捕获，因此在它内部，您可以执行任何您想要的操作，例如删除旧的表，并使用新的形式重新创建它们。|469764|再说一次，不是很聪明，但解决了问题！|469765|entityMap^0|0|0|0|1L|B|0|0|Q|9|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|13|8|@$K|14|L|15|M|N]]|9|@]|A|$]]|$1|O|3|P|5|F|7|16|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|17|8|@$K|18|L|19|M|N]]|9|@]|A|$]]|$1|S|3|T|5|F|7|1A|8|@]|9|@]|A|$G|H]]|$1|U|3|V|5|6|7|1B|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1C|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]]|Z|$]]

I am sure there are many ways to do this (and many ways better then mine as well), but the way that I handle such problems is as follows:

First I define a constant in the first .h file of the app (the one that will load first) to indicate First Time load and set it to 0:

<pre><code>#define FirstTime 0
</code></pre>

Now you have to know that I have the intention to save the value of this constant in the Documents folder for future references, therefore I use a Shared Data Instance. In the <code>viewDidLoad</code> I do the following test:

<pre><code>//if first time run of this version
if( [MyDataModel sharedInstance].count &lt; (FirstTime + 1) )
{
 //do what you need to do as the first time load for this version

 [MyDataModel sharedInstance].count++
 //save the count value to disk so on next run you are not first time
 //this means count = 1
}
</code></pre>

Now the trick is on your new app version (say 1.1). I change the <code>FirstTime</code> to 2:

<pre><code>#define FirstTime 2
</code></pre>

Since the saved First Time value on disc is 1 this means you will be caught by the if statement above, therefore inside it you can do anything you want like delete the old tables and recreate them again with the new formation.

Again not that brilliant, but solves the case!

blocks|key|685879|text|您也可以使用.plist：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|685880|-+(void)isItTheFirstTimeAfterUpdate+{
++++NSString+*versionnum;
++++NSError+*error;
++++NSArray+*paths+=+NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++NSUserDomainMask,
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++YES);
++++NSString+*documentsDirectory+=+[paths+objectAtIndex:0];
++++NSString+*path+=+[documentsDirectory+stringByAppendingPathComponent:@"yourplist.plist"];
++++NSFileManager+*fileManager+=+[NSFileManager+defaultManager];

++++if(![fileManager+fileExistsAtPath:path])+{
++++++++NSString+*bundle+=+[[NSBundle+mainBundle]+pathForResource:@"yourplist"+ofType:@"plist"];
++++++++[fileManager+copyItemAtPath:bundle+toPath:path+error:&error];
++++}

++++NSMutableDictionary+*savedStock+=+[[NSMutableDictionary+alloc]+initWithContentsOfFile:path];
++++versionnum+=+@"";
++++//it+can+be+installed+by+user+(for+ex.+it+is+1.3+but+first+installed),+no+plist+value+is+set+before
++++if(([savedStock+objectForKey:@"versionnum"])+&&+(![[savedStock+objectForKey:@"versionnum"]+isEqualToString:@""])){
++++++++versionnum+=+[savedStock+objectForKey:@"versionnum"];
++++}

++++//to+get+the+version+of+installed/updated-current+app
++++NSString+*myversion+=+[NSString+stringWithFormat:@"%25@",[[[NSBundle+mainBundle]+infoDictionary]+objectForKey:@"CFBundleVersion"]];
++++//if+no+version+has+been+set-first+install-+or+my+version+is+the+latest+version+no+need+to+do+sth.
++++if+([versionnum+isEqualToString:myversion]+%7C%7C+[versionnum+isEqualToString:@""])+{
++++++++NSLog(@"Nothing+has+to+be+done");
++++}
++++else+{
++++++++[self+cleanDB];//i+have+clean+tables+and+create+my+new+db+tables+maybe+logout+the+user+etc.
++++++++[savedStock+setObject:[NSString+stringWithString:myversion]+forKey:@"versionnum"];//setting+the+new+version
++++++++[savedStock+writeToFile:path+atomically:YES];
++++}
}|code-block|syntax|javascript|685881|您可以在应用程序启动时或在主视图控制器的视图控制器中调用该函数。你自己选吧。|685882|希望能有所帮助。|685883|entityMap^0|6|6|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|V|8|@]|D|@]|E|$]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

You can use <code>.plist</code> as well:

<pre><code>- (void)isItTheFirstTimeAfterUpdate {
 NSString *versionnum;
 NSError *error;
 NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
 NSUserDomainMask,
 YES);
 NSString *documentsDirectory = [paths objectAtIndex:0];
 NSString *path = [documentsDirectory stringByAppendingPathComponent:@"yourplist.plist"];
 NSFileManager *fileManager = [NSFileManager defaultManager];

 if(![fileManager fileExistsAtPath:path]) {
 NSString *bundle = [[NSBundle mainBundle] pathForResource:@"yourplist" ofType:@"plist"];
 [fileManager copyItemAtPath:bundle toPath:path error:&amp;error];
 }

 NSMutableDictionary *savedStock = [[NSMutableDictionary alloc] initWithContentsOfFile:path];
 versionnum = @"";
 //it can be installed by user (for ex. it is 1.3 but first installed), no plist value is set before
 if(([savedStock objectForKey:@"versionnum"]) &amp;&amp; (![[savedStock objectForKey:@"versionnum"] isEqualToString:@""])){
 versionnum = [savedStock objectForKey:@"versionnum"];
 }

 //to get the version of installed/updated-current app
 NSString *myversion = [NSString stringWithFormat:@"%@",[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"]];
 //if no version has been set-first install- or my version is the latest version no need to do sth.
 if ([versionnum isEqualToString:myversion] || [versionnum isEqualToString:@""]) {
 NSLog(@"Nothing has to be done");
 }
 else {
 [self cleanDB];//i have clean tables and create my new db tables maybe logout the user etc.
 [savedStock setObject:[NSString stringWithString:myversion] forKey:@"versionnum"];//setting the new version
 [savedStock writeToFile:path atomically:YES];
 }
}
</code></pre>

And you can call the function in application launch or in your main view controller's view controller.. your choice.

hope it helps.

blocks|key|686024|text|这种方法依赖于NSUserDefaults。这个想法是从NSUserDefaults获取以前的应用程序版本号(如果存在)，并将其与当前版本进行比较。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|686025|如果以前的应用程序版本比当前版本更高，或者如果以前的版本是nil，则代码将执行数据库升级。这意味着，即使应用程序已经发布在AppStore上，也可以使用这种方法。它将在应用程序更新期间将数据库升级到新版本。|686026|这是一个plist文件：|686027|​|686028|📷|atomic|686029|686030|有一个数组，它由相应升级版本的版本号和一组sql查询组成。假设以前的版本是1.2，而实际版本是1.4，那么代码只执行从1.2到1.4的升级。如果以前的版本是1.3，而当前的版本是1.4，则代码仅执行从1.3到1.4的升级。如果前一个版本为空，则代码执行升级到1.1，然后升级到1.2，然后升级到1.3，最后升级到1.4。|686031|NSString+*+const+VERSION_KEY+=+@"version";

-(void)upgradeDatabaseIfRequired{
++++NSUserDefaults+*defaults+=+[NSUserDefaults+standardUserDefaults];
++++NSString+*previousVersion=[defaults+objectForKey:VERSION_KEY];
++++NSString+*currentVersion=[self+versionNumberString];

++++if+(previousVersion==nil+%7C%7C+[previousVersion+compare:+currentVersion+options:+NSNumericSearch]+==+NSOrderedAscending)+{
++++++++//+previous+<+current
++++++++//read+upgrade+sqls+from+file
++++++++NSString+*plistPath+=+[[NSBundle+mainBundle]+pathForResource:@"UpgradeDatabase"+ofType:@"plist"];
++++++++NSArray+*plist+=+[NSArray+arrayWithContentsOfFile:plistPath];


++++++++if+(previousVersion==nil)+{//perform+all+upgrades
++++++++++++for+(NSDictionary+*dictionary+in+plist)+{
++++++++++++++++NSString+*version=[dictionary+objectForKey:@"version"];
++++++++++++++++NSLog(@"Upgrading+to+v.+%25@",+version);
++++++++++++++++NSArray+*sqlQueries=[dictionary+objectForKey:@"sql"];
++++++++++++++++while+(![DB+executeMultipleSql:sqlQueries])+{
++++++++++++++++++++NSLog(@"Failed+to+upgrade+database+to+v.+%25@,+Retrying...",+version);
++++++++++++++++};
++++++++++++}
++++++++}else{
++++++++++++for+(NSDictionary+*dictionary+in+plist)+{
++++++++++++++++NSString+*version=[dictionary+objectForKey:@"version"];
++++++++++++++++if+([previousVersion+compare:+version+options:+NSNumericSearch]+==+NSOrderedAscending)+{
++++++++++++++++++++//previous+<+version
++++++++++++++++++++NSLog(@"Upgrading+to+v.+%25@",+version);
++++++++++++++++++++NSArray+*sqlQueries=[dictionary+objectForKey:@"sql"];
++++++++++++++++++++while+(![DB+executeMultipleSql:sqlQueries])+{
++++++++++++++++++++++++NSLog(@"Failed+to+upgrade+database+to+v.+%25@,+Retrying...",+version);
++++++++++++++++++++};
++++++++++++++++}

++++++++++++}
++++++++}

++++++++[defaults+setObject:currentVersion+forKey:VERSION_KEY];
++++++++[defaults+synchronize];
++++}

}


-+(NSString+*)versionNumberString+{
++++NSDictionary+*infoDictionary+=+[[NSBundle+mainBundle]+infoDictionary];
++++NSString+*majorVersion+=+[infoDictionary+objectForKey:@"CFBundleShortVersionString"];
++++return+majorVersion;
}|code-block|syntax|javascript|686032|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/489fb324257d671d671da8eb9fe85d4d.png|imageAlt^0|7|E|S|E|0|T|3|0|0|0|0|1|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|1D|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|1E|8|@]|D|@]|E|$]]|$1|L|3|M|5|N|7|1F|8|@]|D|@$9|1G|A|1H|1|1I]]|E|$]]|$1|O|3|K|5|6|7|1J|8|@]|D|@]|E|$]]|$1|P|3|Q|5|6|7|1K|8|@]|D|@]|E|$]]|$1|R|3|S|5|T|7|1L|8|@]|D|@]|E|$U|V]]|$1|W|3|-4|5|6|7|1M|8|@]|D|@]|E|$]]]|X|$Y|$5|Z|10|11|E|$12|13|14|-4]]]]

This approach relies on <code>NSUserDefaults</code>. The idea is to get the previous app version number(if exists) from <code>NSUserDefaults</code> and compare it with the current version.

The code performs db upgrade if the previous app version <code>&lt;</code> than current version or if the previous version is <code>nil</code>. It means that this approach can be used even though the app was already published on the AppStore. It will upgrade database to the new version during the app update.

This is a plist file:

<img src="https://i.stack.imgur.com/RRFNj.png" alt="enter image description here">

There is an array which is composed of the version number and a set of sql queries for the corresponding upgrade version.
Suppose that a previous version is 1.2 and the actual version is 1.4 the code perform the upgrade only from the version 1.2 to 1.4. If the previous version is 1.3 and the current 1.4 the code performs upgrade only from 1.3 to 1.4.
If the previous version is nil the code performs upgrade to 1.1 then to 1.2 then to 1.3 and finally to 1.4.

<pre><code>NSString * const VERSION_KEY = @"version";

-(void)upgradeDatabaseIfRequired{
 NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
 NSString *previousVersion=[defaults objectForKey:VERSION_KEY];
 NSString *currentVersion=[self versionNumberString];

 if (previousVersion==nil || [previousVersion compare: currentVersion options: NSNumericSearch] == NSOrderedAscending) {
 // previous &lt; current
 //read upgrade sqls from file
 NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"UpgradeDatabase" ofType:@"plist"];
 NSArray *plist = [NSArray arrayWithContentsOfFile:plistPath];


 if (previousVersion==nil) {//perform all upgrades
 for (NSDictionary *dictionary in plist) {
 NSString *version=[dictionary objectForKey:@"version"];
 NSLog(@"Upgrading to v. %@", version);
 NSArray *sqlQueries=[dictionary objectForKey:@"sql"];
 while (![DB executeMultipleSql:sqlQueries]) {
 NSLog(@"Failed to upgrade database to v. %@, Retrying...", version);
 };
 }
 }else{
 for (NSDictionary *dictionary in plist) {
 NSString *version=[dictionary objectForKey:@"version"];
 if ([previousVersion compare: version options: NSNumericSearch] == NSOrderedAscending) {
 //previous &lt; version
 NSLog(@"Upgrading to v. %@", version);
 NSArray *sqlQueries=[dictionary objectForKey:@"sql"];
 while (![DB executeMultipleSql:sqlQueries]) {
 NSLog(@"Failed to upgrade database to v. %@, Retrying...", version);
 };
 }

 }
 }

 [defaults setObject:currentVersion forKey:VERSION_KEY];
 [defaults synchronize];
 }

}


- (NSString *)versionNumberString {
 NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];
 NSString *majorVersion = [infoDictionary objectForKey:@"CFBundleShortVersionString"];
 return majorVersion;
}
</code></pre>

I have an app with version 1.0 on app store which uses sqlite database for reading the data. Now I want to update my version to 1.1 with update in database file. While using developer certificate when I install app on device it did not update the database as the database file already exist in documents folder so i have to manually delete the app and install it again. My question is, when any user update the app, will the database also get updated according the current version. Any suggestions are welcome. Thanks

sqlite database update when app version changes on Appstore in iPhone

数据库

我有一个应用程序与1.0版的应用程序商店，其中使用sqlite数据库读取数据。现在我想在数据库文件中更新我的版本到1.1。使用开发者证书时，当我在设备上安装应用程序时，它没有更新数据库，因为数据库文件已经存在于documents文件夹中，所以我必须手动删除应用程序并重新安装它。我的问题是，当任何用户更新应用程序时，数据...

问当iPhone中应用程序商店上的应用程序版本发生变化时，sqlite数据库会更新
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