【转】Phonegap离线调用SQLite数据库文件

按：不可多得的好文章，转过来以免源丢失

文章来源：http://liuwei.co/index.php/default/The-quickest-way-to-execute-many-sql-for-import-database.html

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客户需要做离线App, 也就是说现在需要将Sqlserver数据库中现有的数据全部初始化至App本地数据库。如果一条条insert，一共有接近70万条数据。显然使用Web sql 5M的容量限制无法满足要求。
于是采用PhoneGap SQLitePlugin,地址: https://github.com/lite4cordova/Cordova-SQLitePlugin为项目添加好插件之后，运行，带来另一个问题，执行insert语句依旧很慢。之后，便采用5000条语句使用一个事务的方式批量插入，对10万条数据进行了测试，如下：

executeSqlBatch icount:0 insertSumCount:20 Time:3:00:29 PM GMT+08:00

executeSqlBatch icount:1 insertSumCount:20 Time:3:00:32 PM GMT+08:00

executeSqlBatch icount:2 insertSumCount:20 Time:3:00:39 PM GMT+08:00

executeSqlBatch icount:3 insertSumCount:20 Time:3:00:48 PM GMT+08:00

executeSqlBatch icount:4 insertSumCount:20 Time:3:01:01 PM GMT+08:00

executeSqlBatch icount:5 insertSumCount:20 Time:3:01:16 PM GMT+08:00

executeSqlBatch icount:6 insertSumCount:20 Time:3:01:35 PM GMT+08:00

executeSqlBatch icount:7 insertSumCount:20 Time:3:01:58 PM GMT+08:00

executeSqlBatch icount:8 insertSumCount:20 Time:3:02:26 PM GMT+08:00

executeSqlBatch icount:9 insertSumCount:20 Time:3:02:56 PM GMT+08:00

executeSqlBatch icount:10 insertSumCount:20 Time:3:03:29 PM GMT+08:00

executeSqlBatch icount:11 insertSumCount:20 Time:3:04:06 PM GMT+08:00

executeSqlBatch icount:12 insertSumCount:20 Time:3:04:47 PM GMT+08:00

executeSqlBatch icount:13 insertSumCount:20 Time:3:05:31 PM GMT+08:00

executeSqlBatch icount:14 insertSumCount:20 Time:3:06:19 PM GMT+08:00

executeSqlBatch icount:15 insertSumCount:20 Time:3:07:08 PM GMT+08:00

executeSqlBatch icount:16 insertSumCount:20 Time:3:08:01 PM GMT+08:00

executeSqlBatch icount:17 insertSumCount:20 Time:3:08:58 PM GMT+08:00

executeSqlBatch icount:18 insertSumCount:20 Time:3:11:13 PM GMT+08:00

executeSqlBatch icount:19 insertSumCount:20 Time:3:12:17 PM GMT+08:00

executeSqlBatch icount:20 insertSumCount:20 Time:3:13:23 PM GMT+08:00

　　

可 以看到，10万条insert语句，采用每5000条语句提交一次事务的方式，一共花了12分54秒。而且每次执行时间比前一次时间要长，并且随着数据量 越大，以后每次的执行时间将更长，因为sqlite采用的是文本形式的数据库，每次对数据库的操作都会进行I/O操作。显然，如此漫长的等待时间，客户是 难以接受的。

最后解决的办法是，将Sqlserver中现有的数据导出成sqlite数据库文件，如xxx.db,之后将该文件放在程序 中，待App第一次启动的时候，将该xxx.db数据库文件拷贝到相应的目录，如android默认是在/data/data/packagename /database目录下，iphone默认是在/Applications/APP串/Documents目录下。
所以，具体的解决办法如下：

Phonegap IOS版:

1,将需要导入的数据库文件拷贝到Resources目录下.

2, AppDelegate.m文件中添加如下代码:

- (void)createEditableCopyOfDatabaseIfNeeded {
// First, test for existence. BOOL success=NO;
BOOL success=NO;
NSString *dbFileName = @"import.db";
NSFileManager *fileManager = [NSFileManager defaultManager];
NSError *error; NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:dbFileName];
success = [fileManager fileExistsAtPath:writableDBPath];
if (success){ NSLog(@"数据库存在");
return;}
// The writable database does not exist, so copy the default to the appropriate location.
NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:dbFileName];
success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];
if (!success) {
NSAssert1(0, @"Failed to create writable database file with message '%@'.", [error localizedDescription]);
}else {
NSLog(@"createEditableCopyOfDatabaseIfNeeded initialize success");
} }

　　

在didFinishLaunchingWithOptions中调用：

[self createEditableCopyOfDatabaseIfNeeded];

3, 在PhoneGap SQLitePlugin中打开数据库的代码为：

db = window.sqlitePlugin.openDatabase({name: "import.db"});

Phonegap Android版：

1,将需要导入的数据库文件拷贝到res/raw目录下.

2,添加DataBaseUtil.java文件

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;

public class DataBaseUtil {

private Context context;
public static String dbName = "texonline.db";// 数据库的名字
private static String DATABASE_PATH;// 数据库在手机里的路径

public DataBaseUtil(Context context) {
this.context = context;
String packageName = context.getPackageName();
DATABASE_PATH="/data/data/"+packageName+"/databases/";
}

/**
* 判断数据库是否存在
*
* @return false or true
*/
public boolean checkDataBase() {
SQLiteDatabase db = null;
try {
String databaseFilename = DATABASE_PATH + dbName;
System.out.println("checkDataBase=>"+databaseFilename);
db = SQLiteDatabase.openDatabase(databaseFilename, null,SQLiteDatabase.OPEN_READONLY);
} catch (SQLiteException e) {

}
if (db != null) {
db.close();
}
return db != null ? true : false;
}

/**
* 复制数据库到手机指定文件夹下
*
* @throws IOException
*/
public void copyDataBase() throws IOException {
String databaseFilenames = DATABASE_PATH + dbName;
File dir = new File(DATABASE_PATH);
if (!dir.exists())// 判断文件夹是否存在，不存在就新建一个
dir.mkdir();
FileOutputStream os = new FileOutputStream(databaseFilenames);// 得到数据库文件的写入流
InputStream is = context.getResources().openRawResource(R.raw.texonline);// 得到数据库文件的数据流
byte[] buffer = new byte[8192];
int count = 0;
while ((count = is.read(buffer)) > 0) {
os.write(buffer, 0, count);
os.flush();
}
is.close();
os.close();
System.out.println("copyDataBase success");
}
}

　　

3,在继承自DroidGap的activity里添加如下方法，并在onCreate里调用。

@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Set by <content src="index.html" /> in config.xml
super.setIntegerProperty("loadUrlTimeoutValue", 60000);
super.loadUrl(Config.getStartUrl(),10000);
copyDataBaseToPhone();
}

private void copyDataBaseToPhone() {
DataBaseUtil util = new DataBaseUtil(this);
// 判断数据库是否存在
boolean dbExist = util.checkDataBase();

if (dbExist) {
Log.i("tag", "The database is exist.");
} else {// 不存在就把raw里的数据库写入手机
try {
util.copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}

　　

4,在PhoneGap SQLitePlugin中打开数据库的代码为：

db = window.sqlitePlugin.openDatabase({name: "import.db"});