Question

我正在为android应用程序编写一个函数，它可以通过导入最新的csv文件来更新sqlite数据库。当用户单击按钮时，程序应该删除旧表并根据最新数据创建另一个新表。当第一次按下按钮时，应用程序能够写入数据。但是，如果数据已经存在，则会发现错误。

05-09 16:41:34.088: E/SQLiteDatabase(3056): Error inserting order_qty=1                                                                                                                                                                                                                                                                  tran_code=NS item_code=IC559 line_no=1 customer_ref_no="PO# 25192600" order_date=20130221 cust_code=099496
05-09 16:41:34.088: E/SQLiteDatabase(3056): android.database.sqlite.SQLiteConstraintException: columns order_date, cust_code, item_code, tran_code are not unique (code 19)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:782)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1469)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1339)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at test.andftpclient.MainActivity$2.onClick(MainActivity.java:118)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.view.View.performClick(View.java:4438)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.view.View$PerformClick.run(View.java:18422)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.os.Handler.handleCallback(Handler.java:733)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.os.Handler.dispatchMessage(Handler.java:95)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.os.Looper.loop(Looper.java:136)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at android.app.ActivityThread.main(ActivityThread.java:5017)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at java.lang.reflect.Method.invokeNative(Native Method)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at java.lang.reflect.Method.invoke(Method.java:515)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-09 16:41:34.088: E/SQLiteDatabase(3056):     at dalvik.system.NativeStart.main(Native Method)

我知道发生此错误的主要原因是插入数据与现有数据具有相同的唯一主键，但我不知道为什么不能删除旧表。这是我的代码：

主要活动

public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);      



    Button button_import_csv = (Button) findViewById(R.id.button_import);
    button_import_csv.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v){


            DatabaseHelper helper = new DatabaseHelper(getApplicationContext());
            SQLiteDatabase db = helper.getWritableDatabase();


            try{

                FileReader file = new FileReader("/sdcard/downloadedfolder/A1/adv_sales_order.csv");
                BufferedReader buffer = new BufferedReader(file);
                ContentValues contentValues=new ContentValues();
                String line = "";
                String tableName ="adv_sales_order";

                db.beginTransaction();
                while ((line = buffer.readLine()) != null) {
                    String[] str = line.split("\t");


                    contentValues.put("order_date", str[0]);
                    contentValues.put("cust_code", str[1]);
                    contentValues.put("customer_ref_no", str[2]);
                    contentValues.put("line_no", str[3]);
                    contentValues.put("item_code", str[4]);
                    contentValues.put("tran_code", str[5]);
                    contentValues.put("order_qty", str[6]);
                    db.insert(tableName, null, contentValues);

                }
                db.setTransactionSuccessful();
                db.endTransaction();
            }catch (IOException e){

            }

            helper.close();
        }
    });
}

}

DatabaseHelper类：

public class DatabaseHelper extends SQLiteOpenHelper {

private static final String DATABASE_NAME = "icedb.db";
private static final int DATABASE_VERSION = 1;
private static final String TABLE_1 = "adv_sales_order";



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

@Override
public void onCreate(SQLiteDatabase db) {
    // TODO Auto-generated method stub

    String CREATE_TB;

    CREATE_TB = "CREATE TABLE adv_sales_order ("
            + "order_date text not null, "
            + "cust_code text not null, "
            + "customer_ref_no text, "
            + "line_no integer not null, "
            + "item_code text not null, "
            + "tran_code text not null, "
            + "order_qty real not null, "
            + "constraint pk_adv_sales_order "
            + "primary key (order_date, "
            + "cust_code, "
            + "item_code, "
            + "tran_code))";
    db.execSQL(CREATE_TB);


}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // TODO Auto-generated method stub

    db.execSQL("DROP TABLE IF EXISTS "+ TABLE_1);

    onCreate(db);
}

public void insert_adv_sales_order (ContentValues values) {
    SQLiteDatabase db = getWritableDatabase();
    db.insert("adv_sales_order", null, values);
    db.close();
}

}

任何人都可以给我一些提示吗？谢谢。

Answer 1

android.database.sqlite.SQLiteConstraintException:
columns order_date, cust_code, item_code, tran_code are not unique (code 19)

在你的create table语句中，你有这个：

"primary key (order_date, cust_code, item_code, tran_code))";

这意味着您的主键是四个列值的组合。每条记录必须具有这些值的唯一组合。无论您插入什么值，看起来都不是这样。

Answer 2

我认为您误解了onCreate和onUpdate的使用。调用onCreate，而不是每次调用getWriteableDatabase，而是在您调用getWriteableDatabase时，当数据库尚不存在时。同样，当现有数据库中的版本号与代码中的版本号不匹配时，将调用onUpdate。

为了删除表格，给定您的代码，我想，您可以明确地将onUpdate称为函数insert_adv_sales_order的第二行。

getWritableDatabase不起作用

2 个答案: