如何在sqlite中添加数据库中的第二个表？

Question

我有数据库examguide,我已经创建了一个表table_subject,现在
我想table_chapter在这个数据库中创建第二个table().我的问题是如何在现有数据库中添加此表？我有以下代码.任何帮助赞赏.

private static final String DATABASE_CREATE = "create table IF NOT EXISTS "
        + TABLE_SUBJECT + "( " + COLUMN_ID
        + " integer primary key autoincrement, " 
        + COLUMN_SUBJECT + " text not null, "
        + COLUMN_CHAPTER + " text, "
        + COLUMN_QUESTION + " text not null,"
        + COLUMN_OPTIONA + " text not null,"
        + COLUMN_OPTIONB + " text not null,"
        + COLUMN_OPTIONC + " text not null,"
        + COLUMN_OPTIOND + " text not null,"
        + COLUMN_CORRECT + " text not null,"
        + COLUMN_CONFIRM + " text not null);";

    private static final String DATABASE_CREATE1 = "create table IF NOT EXISTS "
    + TABLE_CHAPTER + "( " + COLUMN_ID
    + " integer primary key autoincrement, " 
    + COLUMN_SUBJECT + " text not null, "
    + COLUMN_CHAPTER + " text, "
    + COLUMN_QUESTION + " text not null,"
    + COLUMN_OPTIONA + " text not null,"
    + COLUMN_OPTIONB + " text not null,"
    + COLUMN_OPTIONC + " text not null,"
    + COLUMN_OPTIOND + " text not null,"
    + COLUMN_CORRECT + " text not null,"
    + COLUMN_CONFIRM + " text not null);";

public MySQLiteHelper open() throws SQLException 
{
    db = this.getWritableDatabase();
    return this;
}

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

}


@Override
public void onCreate(SQLiteDatabase database) {

    database.execSQL(DATABASE_CREATE);
    database.execSQL(DATABASE_CREATE1);

}

此代码不会创建第二个表.我想在我的数据库中使用这两个表.
它在logcat中显示以下错误.

03-21 18:31:06.551: ERROR/Database(8255): Error inserting chapter=paging correctoption=shadow copy craete a duplicate copy of page subject=operating system question=what is shadow copy? optiona=shadow copy craete a duplicate copy of page confirm=YES optionb=sahdow copy create paging  optionc=shadow copy delete duplicate page optiond=shadow copy delete original and create shadow copy
03-21 18:31:06.551: ERROR/Database(8255): android.database.sqlite.SQLiteException: no such table: chapter: , while compiling: INSERT INTO chapter(chapter, correctoption, subject, question, optiona, confirm, optionb, optionc, optiond) VALUES(?, ?, ?, ?, ?, ?, ?, ?, ?);
03-21 18:31:06.551: ERROR/Database(8255):     at android.database.sqlite.SQLiteCompiledSql.native_compile(Native Method)
03-21 18:31:06.551: ERROR/Database(8255):     at android.database.sqlite.SQLiteCompiledSql.compile(SQLiteCompiledSql.java:92)
03-21 18:31:06.551: ERROR/Database(8255):     at   android.database.sqlite.SQLiteCompiledSql.<init>(SQLiteCompiledSql.java:65)
03-21 18:31:06.551: ERROR/Database(8255):     at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:83)
03-21 18:31:06.551: ERROR/Database(8255):     at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:41)
03-21 18:31:06.551: ERROR/Database(8255):     at android.database.sqlite.SQLiteDatabase.compileStatement(SQLiteDatabase.java:1149)
03-21 18:31:06.551: ERROR/Database(8255):     at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1569)
03-21 18:31:06.551: ERROR/Database(8255):     at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1426)
03-21 18:31:06.551: ERROR/Database(8255):     at com.example.examguide.MySQLiteHelper.insertChapterData(MySQLiteHelper.java:212)
03-21 18:31:06.551: ERROR/Database(8255):     at com.example.examguide.ObjectiveAddActivity$2.onClick(ObjectiveAddActivity.java:155)

Answer 1

制作另一个CREATE TABLE字符串,然后在你的onCreate,execSQL再次打电话:

database.execSQL(DATABASE_CREATE1);
database.execSQL(DATABASE_CREATE2);

编辑

要将另一个表添加到现有数据库,请onUpgrade按如下方式修改方法.onUpgrade每当数据库需要升级时调用; 请注意,您必须增加VERSION_NUMBER(您希望在类中包含为私有实例变量)才能使其生效.

@Override
public void onUpgrade (SQLiteDatabase db, int oldVersion, int newVersion) {
    db.executeSQL(DATABASE_CREATE2);
}

Answer 2

如果要将表添加到现有数据库,请使用以下onUpgrade() 方法MySqliteHelper:

@Override
public void onUpgrade (SQLiteDatabase db, int oldVersion, int newVersion) {
    // Create the string for the second table creation
    db.executeSQL(DATABASE_CREATE_SECOND_TABLE);
}

并且还会增加传递给MySqliteHelper构造函数的数据库版本的值(如果传递1然后传递2).