java - Android SQLite 问题 - 表 __ 没有名为 ___ 的列

Question

我是一名新开发人员，我遇到了 SQLite 问题。由于某些原因，我无法将两列(table_row_three 和 table_row_four)添加到我的 SQLite 数据表中。当我当前读取数据库文件时，它有一个包含“id”、“table_row_one”和“table_row_two”的表，但缺少“table_row_three”和“table_row_four”。

我的 logcat 中的错误消息是:“(1) 表 database_table 没有名为 table_row_three 的列”。

我真的很困惑为什么“table_row_three”和“table_row_four”列没有显示在我的表中，为什么我的数据表中只出现“id”、“table_row_one”和“table_row_two”。

这是我的数据库类:

DatabaseHandler.java


import java.util.ArrayList;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;



public class DatabaseHandler
{

Context context;


private SQLiteDatabase db;


private final String DB_NAME = "database_name";
private final int DB_VERSION = 2;


private final String TABLE_NAME = "database_table";
private final String TABLE_ROW_ID = "id";

private final String TABLE_ROW_ONE = "table_row_one";
private final String TABLE_ROW_TWO = "table_row_two";
private final String TABLE_ROW_THREE = "table_row_three";
private final String TABLE_ROW_FOUR = "table_row_four";

public DatabaseHandler(Context context)
{
    this.context = context;

    // create or open the database
    CustomSQLiteOpenHelper helper = new CustomSQLiteOpenHelper(context);
    this.db = helper.getWritableDatabase();
}


public void addRow(String rowStringOne, String rowStringTwo, String rowStringThree, String rowStringFour)
{
    // this is a key value pair holder used by android's SQLite functions
    ContentValues values = new ContentValues();
    //TABLE_ROW_ONE = Title
    //TABLE_ROW_TWO = Location
    //TABLE_ROW_THREE = Notes
    //TABLE_ROW_FOUR = Picture
    values.put(TABLE_ROW_ONE, rowStringOne);
    values.put(TABLE_ROW_TWO, rowStringTwo);
    values.put(TABLE_ROW_THREE, rowStringThree);
    values.put(TABLE_ROW_FOUR, rowStringFour);

    // ask the database object to insert the new data
    try{db.insert(TABLE_NAME, null, values);}
    catch(Exception e)
    {
        Log.e("DB ERROR", e.toString());
        e.printStackTrace();
    }
}




public void deleteRow(long rowID)
{
    // ask the database manager to delete the row of given id
    try {db.delete(TABLE_NAME, TABLE_ROW_ID + "=" + rowID, null);}
    catch (Exception e)
    {
        Log.e("DB ERROR", e.toString());
        e.printStackTrace();
    }
}

public void updateRow(long rowID, String rowStringOne, String rowStringTwo, String rowStringThree, String rowStringFour)
{
    ContentValues values = new ContentValues();
    values.put(TABLE_ROW_ONE, rowStringOne);
    values.put(TABLE_ROW_TWO, rowStringTwo);
    values.put(TABLE_ROW_THREE, rowStringThree);
    values.put(TABLE_ROW_FOUR, rowStringFour);

    try {db.update(TABLE_NAME, values, TABLE_ROW_ID + "=" + rowID, null);}
    catch (Exception e)
    {
        Log.e("DB Error", e.toString());
        e.printStackTrace();
    }
}


public ArrayList<Object> getRowAsArray(long rowID)
{

    ArrayList<Object> rowArray = new ArrayList<Object>();
    Cursor cursor;

    try
    {

        cursor = db.query
                (
                        TABLE_NAME,
                        new String[] { TABLE_ROW_ID, TABLE_ROW_ONE, TABLE_ROW_TWO, TABLE_ROW_THREE, TABLE_ROW_FOUR },
                        TABLE_ROW_ID + "=" + rowID,
                        null, null, null, null, null
                );


        cursor.moveToFirst();


        if (!cursor.isAfterLast())
        {
            do
            {
                rowArray.add(cursor.getLong(0));
                rowArray.add(cursor.getString(1));
                rowArray.add(cursor.getString(2));
                rowArray.add(cursor.getString(3));
                rowArray.add(cursor.getString(4));
            }
            while (cursor.moveToNext());
        }


        cursor.close();
    }
    catch (SQLException e)
    {
        Log.e("DB ERROR", e.toString());
        e.printStackTrace();
    }

    // return the ArrayList containing the given row from the database.
    return rowArray;
}






public ArrayList<ArrayList<Object>> getAllRowsAsArrays()
{

    ArrayList<ArrayList<Object>> dataArrays = new ArrayList<ArrayList<Object>>();


    Cursor cursor;

    try
    {
        cursor = db.query(
                TABLE_NAME,
                new String[]{TABLE_ROW_ID, TABLE_ROW_ONE, TABLE_ROW_TWO, TABLE_ROW_THREE, TABLE_ROW_FOUR},
                null, null, null, null, null
        );

        cursor.moveToFirst();

        if (!cursor.isAfterLast())
        {
            do
            {
                ArrayList<Object> dataList = new ArrayList<Object>();

                dataList.add(cursor.getLong(0));
                dataList.add(cursor.getString(1));
                dataList.add(cursor.getString(2));
                dataList.add(cursor.getString(3));
                dataList.add(cursor.getString(4));
                dataArrays.add(dataList);
            }
            while (cursor.moveToNext());
        }
    }
    catch (SQLException e)
    {
        Log.e("DB Error", e.toString());
        e.printStackTrace();
    }

    return dataArrays;
}








private class CustomSQLiteOpenHelper extends SQLiteOpenHelper
{
    public CustomSQLiteOpenHelper(Context context)
    {
        super(context, DB_NAME, null, DB_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db)
    {

        String newTableQueryString = "create table " +
                TABLE_NAME +
                " (" +
                TABLE_ROW_ID + " integer primary key autoincrement not null," +
                TABLE_ROW_ONE + " text," +
                TABLE_ROW_TWO + " text" +
                TABLE_ROW_THREE + " text" +
                TABLE_ROW_FOUR + " text" +
                ");";
        db.execSQL(newTableQueryString);
    }


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

    }
}

这是我的测试类:

public class DatabaseExampleActivity extends Activity {
EditText textFieldOne, textFieldTwo, textFieldThree, textFieldFour,
        idField,
        updateIDField, updateTextFieldOne, updateTextFieldTwo,updateTextFieldThree, updateTextFieldFour;

Button addButton, deleteButton, retrieveButton, updateButton;

TableLayout dataTable;

DatabaseHandler db;



@Override
public void onCreate(Bundle savedInstanceState) {
    // this try catch block returns better error reporting to the log
    try {
        // Android specific calls
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_databaseexample);

        // create the database manager object
        db = new DatabaseHandler(this);

        // create references and listeners for the GUI interface
        setupViews();

        // make the buttons clicks perform actions
        addButtonListeners();

        // load the data table
        updateTable();
    } catch (Exception e) {
        Log.e("ERROR", e.toString());
        e.printStackTrace();
    }
}


private void setupViews() {
    // THE DATA TABLE
    dataTable = (TableLayout) findViewById(R.id.data_table);

    // THE DATA FORM FIELDS
    textFieldOne = (EditText) findViewById(R.id.text_field_one);
    textFieldTwo = (EditText) findViewById(R.id.text_field_two);
    textFieldThree = (EditText) findViewById(R.id.text_field_three);
    textFieldFour = (EditText) findViewById(R.id.text_field_four);
    idField = (EditText) findViewById(R.id.id_field);
    updateIDField = (EditText) findViewById(R.id.update_id_field);
    updateTextFieldOne = (EditText) findViewById(R.id.update_text_field_one);
    updateTextFieldTwo = (EditText) findViewById(R.id.update_text_field_two);
    updateTextFieldThree = (EditText) findViewById(R.id.update_text_field_three);
    updateTextFieldFour = (EditText) findViewById(R.id.update_text_field_four);

    addButton = (Button) findViewById(R.id.add_button);
    deleteButton = (Button) findViewById(R.id.delete_button);
    retrieveButton = (Button) findViewById(R.id.retrieve_button);
    updateButton = (Button) findViewById(R.id.update_button);
}



private void addButtonListeners() {
    addButton.setOnClickListener
            (
                    new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            addRow();
                        }
                    }
            );

    deleteButton.setOnClickListener
            (
                    new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            deleteRow();
                        }
                    }
            );

    updateButton.setOnClickListener
            (
                    new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            updateRow();
                        }
                    }
            );

    retrieveButton.setOnClickListener
            (
                    new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            retrieveRow();
                        }
                    }
            );

}


private void addRow() {
    try {
        // ask the database manager to add a row given the two strings
        db.addRow
                (
                        textFieldOne.getText().toString(),
                        textFieldTwo.getText().toString(),
                        textFieldThree.getText().toString(),
                        textFieldFour.getText().toString()

                );

        // request the table be updated
        updateTable();

        // remove all user input from the Activity
        emptyFormFields();
    } catch (Exception e) {
        Log.e("Add Error", e.toString());
        e.printStackTrace();
    }
}


private void deleteRow() {
    try {
        // ask the database manager to delete the row with the give rowID.
        db.deleteRow(Long.parseLong(idField.getText().toString()));

        // request the table be updated
        updateTable();

        // remove all user input from the Activity
        emptyFormFields();
    } catch (Exception e) {
        Log.e("Delete Error", e.toString());
        e.printStackTrace();
    }
}


private void retrieveRow() {
    try {
        // The ArrayList that holds the row data
        ArrayList<Object> row;
        // ask the database manager to retrieve the row with the given rowID
        row = db.getRowAsArray(Long.parseLong(updateIDField.getText().toString()));

        // update the form fields to hold the retrieved data
        updateTextFieldOne.setText((String) row.get(1));
        updateTextFieldTwo.setText((String) row.get(2));
        updateTextFieldThree.setText((String) row.get(3));
        updateTextFieldFour.setText((String) row.get(4));

    } catch (Exception e) {
        Log.e("Retrieve Error", e.toString());
        e.printStackTrace();
    }
}

private void updateRow() {
    try {
        // ask the database manager to update the row based on the information
        // found in the corresponding user entry fields
        db.updateRow
                (
                        Long.parseLong(updateIDField.getText().toString()),
                        updateTextFieldOne.getText().toString(),
                        updateTextFieldTwo.getText().toString(),
                        updateTextFieldThree.getText().toString(),
                        updateTextFieldFour.getText().toString()
                );

        updateTable();

        emptyFormFields();
    } catch (Exception e) {
        Log.e("Update Error", e.toString());
        e.printStackTrace();
    }
}


private void emptyFormFields() {
    textFieldOne.setText("");
    textFieldTwo.setText("");
    textFieldThree.setText("");
    textFieldFour.setText("");
    idField.setText("");
    updateIDField.setText("");
    updateTextFieldOne.setText("");
    updateTextFieldTwo.setText("");
    updateTextFieldThree.setText("");
    updateTextFieldFour.setText("");
}


private void updateTable() {
    // delete all but the first row.  remember that the count
    // starts at one and the index starts at zero
    while (dataTable.getChildCount() > 1) {
        // while there are at least two rows in the table widget, delete
        // the second row.
        dataTable.removeViewAt(1);
    }

    // collect the current row information from the database and
    // store it in a two dimensional ArrayList
    ArrayList<ArrayList<Object>> data = db.getAllRowsAsArrays();

    // iterate the ArrayList, create new rows each time and add them
    // to the table widget.
    for (int position = 0; position < data.size(); position++) {
        TableRow tableRow = new TableRow(this);

        ArrayList<Object> row = data.get(position);

        TextView idText = new TextView(this);
        idText.setText(row.get(0).toString());
        tableRow.addView(idText);

        TextView textOne = new TextView(this);
        textOne.setText(row.get(1).toString());
        tableRow.addView(textOne);

        TextView textTwo = new TextView(this);
        textTwo.setText(row.get(2).toString());
        tableRow.addView(textTwo);


        TextView textThree = new TextView(this);
        textThree.setText(row.get(3).toString());
        tableRow.addView(textThree);


        TextView textFour = new TextView(this);
        textFour.setText(row.get(4).toString());
        tableRow.addView(textFour);


        dataTable.addView(tableRow);
    }
}

Answer 1

创建语句中缺少“,”:

String newTableQueryString = "create table " +
     TABLE_NAME +
     " (" +
     TABLE_ROW_ID + " integer primary key autoincrement not null," +
     TABLE_ROW_ONE + " text," +
     TABLE_ROW_TWO + " text," +
     TABLE_ROW_THREE + " text," +
     TABLE_ROW_FOUR + " text" +
     ");";