android 动态更新sql

最新推荐文章于 2021-05-29 00:35:10 发布

Android西红柿

最新推荐文章于 2021-05-29 00:35:10 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/fumeidonga/article/details/50921007

本文介绍了一种不需版本更新即可更新数据库的方法，通过下载SQL文件并在线执行，实现数据库的高效升级。

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我们做项目是会遇到需要更新数据库，但是又不想发版本的情况，

这时可以从服务器下载sql文件，然后依次执行

1 ，downLoadFile

2，读取文件流，然后执行sql语句

File LocalFile = new File(sqlfilepath);
if (LocalFile.exists()) {
InputStreamReader reader = null;
try {
reader = new InputStreamReader(new FileInputStream(LocalFile), "utf-8");
int c;
StringBuffer sb = new StringBuffer();
char buffer[] = new char[1024];
while ((c = reader.read(buffer, 0, 1024)) != -1) {
sb.append(new String(buffer, 0, c));
}
String sqlStr = sb.toString();
sqlStr = sqlStr.replaceAll("\r\n", "");
String[] sqlStrs = sqlStr.split(";");
for (String sql : sqlStrs) {
getDbUtils().execNonQuery(sql);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}

3 another

/**
 * This reads a file from the given Resource-Id and calls every line of it as a SQL-Statement
 * 
 * @param context
 *  
 * @param resourceId
 *  e.g. R.raw.food_db
 * 
 * @return Number of SQL-Statements run
 * @throws IOException
 */
public int insertFromFile(Context context, int resourceId) throws IOException {
    // Reseting Counter
    int result = 0;

    // Open the resource
    InputStream insertsStream = context.getResources().openRawResource(resourceId);
    BufferedReader insertReader = new BufferedReader(new InputStreamReader(insertsStream));

    // Iterate through lines (assuming each insert has its own line and theres no other stuff)
    while (insertReader.ready()) {
        String insertStmt = insertReader.readLine();
        db.execSQL(insertStmt);
        result++;
    }
    insertReader.close();

    // returning number of inserted rows
    return result;
}