我在android应用中编写数据库,但未创建表。我在onCreate方法和getWriteableDatabase处添加了断点,并调用了getWritableDatabase,但未创建onCreate。

package com.fslade.app;

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

public class DatabaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "applicationdata";
    private static final int DATABASE_VERSION = 1;
    public static final String DATABASE_TABLE = "peopleT";

    // Database creation sql statement
    private static final String DATABASE_CREATE = "create table " + DATABASE_TABLE + " (_id integer primary key autoincrement, "
            + "company_name text not null, name text not null, city text not null, vertical text not null, title text not null, email text not null, bio text not null, photo text not null, status text not null);";

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

    // Method is called during creation of the database
    @Override
    public void onCreate(SQLiteDatabase database) {
        database.execSQL(DATABASE_CREATE);
    }

    // Method is called during an upgrade of the database, e.g. if you increase
    // the database version
    @Override
    public void onUpgrade(SQLiteDatabase database, int oldVersion,
            int newVersion) {
        Log.w(DatabaseHelper.class.getName(),
                "Upgrading database from version " + oldVersion + " to "
                        + newVersion + ", which will destroy all old data");
        database.execSQL("DROP TABLE IF EXISTS todo");
        onCreate(database);
    }
}

在数据库助手中,我调用getWriteableDatabse():
package com.fslade.app;

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

public class ContentStorageHelper {
    public static final String KEY_ID = "_id";
    public static final String KEY_COMPANY_NAME = "company_name";
    public static final String KEY_PERSON_NAME = "name";
    public static final String KEY_CITY = "city";
    public static final String KEY_VERTICAL = "vertical";
    public static final String KEY_TITLE = "title";
    public static final String KEY_EMAIL = "email";
    public static final String KEY_BIO = "bio";
    public static final String KEY_PHOTO = "photo";
    public static final String KEY_STATUS = "status";

    private static final String[] COLUMNS = { KEY_ID, KEY_COMPANY_NAME,
            KEY_PERSON_NAME, KEY_CITY, KEY_VERTICAL, KEY_TITLE, KEY_EMAIL,
            KEY_BIO, KEY_PHOTO, KEY_STATUS };

    private Context context;
    private SQLiteDatabase database;
    private DatabaseHelper dbHelper;

    public ContentStorageHelper(Context context) {
        this.context = context;
    }

    public ContentStorageHelper open() throws SQLException {
        dbHelper = new DatabaseHelper(context);
        database = dbHelper.getWritableDatabase();
        // dbHelper.onCreate(database);
// I added this onCreate() to see if it helped, but when I ran it
// it said that the database had already been created
        return this;
    }

    public void close() {
        dbHelper.close();
    }

/**
 * Create a new person If the person is successfully created return the new
 * rowId for that person, otherwise return a -1 to indicate failure.
 */
public long createPerson(String company_name, String name, String city,
        String vertical, String title, String email, String bio,
        String photo, String status) {
    ContentValues initialValues = createContentValues(company_name, name,
            city, vertical, title, email, bio, photo, status);

    return database.insert(DatabaseHelper.DATABASE_TABLE, null,
            initialValues);
}

/**
 * Return a Cursor over the list of all people in the database
 *
 * @return Cursor over all notes
 */
public Cursor fetchPeopleByVertical(String vertical) {
    String selection = KEY_VERTICAL+"="+vertical;
        Cursor result = database.query(DatabaseHelper.DATABASE_TABLE, COLUMNS,
                selection, null, null, null, null);
        return result;
    }

    private ContentValues createContentValues(String company_name, String name,
            String city, String vertical, String title, String email,
            String bio, String photo, String status) {
        ContentValues values = new ContentValues();
        values.put(KEY_COMPANY_NAME, company_name);
        values.put(KEY_PERSON_NAME, name);
        values.put(KEY_CITY, city);
        values.put(KEY_VERTICAL, vertical);
        values.put(KEY_TITLE, title);
        values.put(KEY_EMAIL, email);
        values.put(KEY_BIO, bio);
        values.put(KEY_PHOTO, photo);
        values.put(KEY_STATUS, status);
        System.out.print("test: " + status);
        return values;
    }
}

最佳答案

创建仅发生一次(这就是数据库助手的全部含义)。

您是否检查数据库是否已创建?它位于/data/data/your.package.name/databases/dbname

如果您在android应用程序设置中清除了应用程序数据,则应再次调用onCreate ...

10-05 20:34
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