Question

我正在学习如何在SQLite DB中创建和插入值。该应用程序有一个按钮和计时器。单击按钮启动计时器并再次单击它会停止计时器。停止时，值将存储到DB中。我可以从Android Studio中的文件资源管理器中看到数据库和表正在创建。日志中有证据表明开始和停止时间也被捕获，但值未插入数据库。我正在粘贴用于创建数据库的代码片段，然后插入记录。我也是在输出错误的日志片段。请帮忙。

   import android.content.ContentValues; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.content.Context; import android.util.Log; import java.util.ArrayList; import java.util.LinkedList; import java.util.List; public class DBHelper extends SQLiteOpenHelper {

        public static final int DATABASE_VERSION = 1;
        public static final String DATABASE_NAME = "Feeds.db";
        public static String TIMESTAMP_START;
        public static String   TIMESTAMP_END;
        public static int _ID = 0;
        public static final String DATABASE_TABLE = "T_FEEDRECORDS";
        private static final String SQL_CREATE_ENTRIES = "CREATE TABLE T_FEEDRECORDS ( _ID  INTEGER primary key autoincrement,  TIMESTAMP_START TEXT, TIMESTAMP_END TEXT)" ;

        public DBHelper(Context context)
        {
            super(context,DATABASE_NAME, null, DATABASE_VERSION );
        }


        public void onCreate(SQLiteDatabase db)
        {
            Log.d("onCreate", "before DB Create");
            try {
                db.execSQL(SQL_CREATE_ENTRIES);
            } catch(SQLException ex){ Log.d("onCreate", "DB creation exception:"+ ex.getMessage()); }
            Log.d("onCreate", "after DB Create" + db.toString());
        }

        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
        {

            db.execSQL("DROP TABLE IF IT EXISTS " + DATABASE_TABLE);
            Log.d("onUpgrade", "dropping table");
             onCreate(db);
        }

        public void createFeedRecord (FeedRecords feedRecord){
            ContentValues feedContent = new ContentValues();
            feedContent.put(TIMESTAMP_START,  feedRecord.getStartTime());
            feedContent.put(TIMESTAMP_END,  feedRecord.getEndTime());
            try {
                SQLiteDatabase db = this.getWritableDatabase();
                Log.d("createFeedRecord values before insert", "start time : " + feedRecord.getStartTime() + " Timer end:" + feedRecord.getEndTime());
                db.insertOrThrow(DATABASE_TABLE,null, feedContent );
                db.close();
            } catch(SQLException ex) {Log.d("SQL Exdception in create feed record", "" + ex.getLocalizedMessage());}
            Log.d("createFeedRecord", "after content values");
        } 
}

LOG SNIPPET

02-04 09:57:43.287    2213-2213/? D/onClick......﹕ Timer Start time: 150204_095743
....
02-04 10:01:25.738    2213-2213/? D/onClick......﹕ Timer Stop time: 150204_100125
02-04 10:01:25.738    2213-2213/? D/inster Time Record﹕ after create Feed
02-04 10:01:25.754    1239-1293/? W/AudioTrack﹕ AUDIO_OUTPUT_FLAG_FAST denied by client

02-04 10:01:25.763    2213-2213/? D/createFeedRecord values before insert﹕ start time : 150204_095743 Timer end:150204_100125
02-04 10:01:25.763    2213-2213/? E/SQLiteLog﹕ (1) near "null": syntax error
02-04 10:01:25.763    2213-2213/? D/SQL Exdception in create feed record﹕ near "null": syntax error (code 1): , while compiling: INSERT INTO T_FEEDRECORDS(null) VALUES (?)
02-04 10:01:25.763    2213-2213/? D/createFeedRecord﹕ after content values

Answer 1

您需要指定

  public static String TIMESTAMP_START="TIMESTAMP_START";
  public static String TIMESTAMP_END="TIMESTAMP_END";

或

直接提供列名

ContentValues feedContent = new ContentValues(); feedContent.put("TIMESTAMP_START", feedRecord.getStartTime()); feedContent.put("TIMESTAMP_END", feedRecord.getEndTime());

接近“null”：语法错误（代码1）:,编译时：INSERT INTO

1 个答案:

或