私は Android で SQLite データベースを初めて使用するので、少し助けが必要です。私が作成しようとしているアプリは、ユーザーのワークアウト エクササイズと各エクササイズの担当者を保存します。1 つのエクササイズを保存するデータベースをセットアップして動作させていますが、onUpgrade() メソッドを動作させることができないため、残りのエクササイズでより大きなデータベースを作成できます。
元のコードは、次の列を持つデータベースを作成しました
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" +
KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
KEY_EXERCISE + " TEXT NOT NULL, " +
KEY_EX1REPS1 + " TEXT NOT NULL," +
KEY_EX1REPS2 + " TEXT NOT NULL," +
KEY_EX1REPS3 + " TEXT NOT NULL);"
);
}
しかし、たとえば次のように追加したい
KEY_EXERCISE2 + " TEXT NOT NULL, " +
KEY_EX2REPS1 + " TEXT NOT NULL," +
KEY_EX2REPS2 + " TEXT NOT NULL," +
KEY_EX2REPS3 + " TEXT NOT NULL);
以下の onUpgrade メソッドを使用してこれを実行しようとしましたが、機能しません
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS" + DATABASE_TABLE);
onCreate(db);
}
追加の列を追加する方法を誰かが教えてくれたら、大歓迎です。以下は、完全な database.java ファイルです。
public class Database {
public static final String KEY_ROWID = "_id";
public static final String KEY_EXERCISE = "exercise_name";
public static final String KEY_EX1REPS1 = "exercise_rep1";
public static final String KEY_EX1REPS2 = "exercise_rep2";
public static final String KEY_EX1REPS3 = "exercise_rep3";
public static final String KEY_EXERCISE2 = "exercise2_name";
public static final String KEY_EX2REPS1 = "exercise2_rep1";
public static final String KEY_EX2REPS2 = "exercise2_rep2";
public static final String KEY_EX2REPS3 = "exercise2_rep3";
private DbHelper ourHelper; //just a insince of the DbHelper class
private final Context ourContext;
public static SQLiteDatabase ourDatabase;
public static final int COL_ROWID = 0;
private static final String DATABASE_NAME = "Workouts";
static final String DATABASE_TABLE = "exercisesandreps";
private static final int DATABASE_VERSION = 2;
public static final String[] ALL_KEYS = new String[] {KEY_ROWID, KEY_EXERCISE, KEY_EX1REPS1, KEY_EX1REPS2, KEY_EX1REPS3, KEY_EXERCISE2, KEY_EX2REPS1, KEY_EX2REPS2, KEY_EX2REPS3};
private static class DbHelper extends SQLiteOpenHelper{
public DbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
//context, name, factory, version
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" +
KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + //each one of these lines defines a column of the database
KEY_EXERCISE + " TEXT NOT NULL, " +
KEY_EX1REPS1 + " TEXT NOT NULL," +
KEY_EX1REPS2 + " TEXT NOT NULL," +
KEY_EX1REPS3 + " TEXT NOT NULL," +
KEY_EXERCISE2 + " TEXT NOT NULL, " +
KEY_EX2REPS1 + " TEXT NOT NULL," +
KEY_EX2REPS2 + " TEXT NOT NULL," +
KEY_EX2REPS3 + " TEXT NOT NULL);"
);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS" + DATABASE_TABLE);
onCreate(db);
}
}
public Database(Context c){
ourContext = c;
}
public Database open() throws SQLException{
ourHelper = new DbHelper(ourContext);
ourDatabase = ourHelper.getWritableDatabase(); //use writable because if you can write to it, you can read it
return this;
}
public void close(){
ourHelper.close();
}
public long createEntry(String Exercise, String Ex1R1, String Ex1R2, String Ex1R3, String Exercise2, String Ex2R1, String Ex2R2, String Ex2R3) {
// TODO Auto-generated method stub
ContentValues cv = new ContentValues();
//String Exercise1 = convertArrayToString(ExerciseArray);
cv.put(KEY_EXERCISE, Exercise);
cv.put(KEY_EX1REPS1, Ex1R1);
cv.put(KEY_EX1REPS2, Ex1R2);
cv.put(KEY_EX1REPS3, Ex1R3);
cv.put(KEY_EXERCISE2, Exercise2);
cv.put(KEY_EX2REPS1, Ex2R1);
cv.put(KEY_EX2REPS2, Ex2R2);
cv.put(KEY_EX2REPS3, Ex2R3);
return ourDatabase.insert(DATABASE_TABLE, null, cv); //this will crash if you haven't set up a table with rows + columns
}
public String getData() {
// TODO Auto-generated method stub
String[] columns = new String[]{KEY_ROWID, KEY_EXERCISE, KEY_EX1REPS1, KEY_EX1REPS2, KEY_EX1REPS3, KEY_EXERCISE2, KEY_EX2REPS1, KEY_EX2REPS2, KEY_EX2REPS3};
//you read information through a cursor
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
String result = "";
//these keep track of the current row, name, hotness
int iRow = c.getColumnIndex(KEY_ROWID);//position 0
int iExercise1 = c.getColumnIndex(KEY_EXERCISE);//position 1
int iEx1R1 = c.getColumnIndex(KEY_EX1REPS1);//position 2
int iEx1R2 = c.getColumnIndex(KEY_EX1REPS2);//position 3
int iEx1R3 = c.getColumnIndex(KEY_EX1REPS3);//position 4
int iExercise2 = c.getColumnIndex(KEY_EXERCISE);//position 1
int iEx2R1 = c.getColumnIndex(KEY_EX1REPS1);//position 2
int iEx2R2 = c.getColumnIndex(KEY_EX1REPS2);//position 3
int iEx2R3 = c.getColumnIndex(KEY_EX1REPS3);//position 4
for(c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){ //!c.isAfterLast = if our cursor is not after the last entry in our database
//starting at the first position, it will move one each go unless it hasn't exceeded the last entry
result = result + c.getString(iRow) + " " + c.getString(iExercise1) + " " + c.getString(iEx1R1) + " " + c.getString(iEx1R2) + " " + c.getString(iEx1R3) +
c.getString(iExercise2) + " " + c.getString(iEx2R1) + " " + c.getString(iEx2R2) + " " + c.getString(iEx2R3) +
"\n";
}
return result;
}
public String getExercise(long l) throws SQLException{
// TODO Auto-generated method stub
String[] columns = new String[]{KEY_ROWID, KEY_EXERCISE, KEY_EX1REPS1, KEY_EX1REPS2, KEY_EX1REPS3, KEY_EXERCISE2, KEY_EX2REPS1, KEY_EX2REPS2, KEY_EX2REPS3};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ROWID + "=" + l,null, null, null, null);
if(c != null){
c.moveToFirst();
String exercise = c.getString(1);//we know the name column is the second column in the database so it will have a position 1
return exercise;//the code will only return the name if the cursor is set to null
}
return null;
}
public String[] getReps1(long l) throws SQLException{
// TODO Auto-generated method stub
String[] columns = new String[]{KEY_ROWID, KEY_EXERCISE, KEY_EX1REPS1, KEY_EX1REPS2, KEY_EX1REPS3};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ROWID + "=" + l,null, null, null, null);
if(c != null){
c.moveToFirst();
String reps1 = c.getString(2);//we know the name column is the second column in the database so it will have a position 1
String reps2 = c.getString(3);
String reps3 = c.getString(4);
String[] result = new String[]{reps1, reps2, reps3};
return result;//the code will only return the name if the cursor is set to null
}
return null;
}
public void updateEntry (long lRow, String mExercise, String mEx1Reps1, String mEx1Reps2, String mEx1Reps3) throws SQLException{
// TODO Auto-generated method stub
ContentValues cvUpdate = new ContentValues();
cvUpdate.put(KEY_EXERCISE, mExercise);
cvUpdate.put(KEY_EX1REPS1, mEx1Reps1);
cvUpdate.put(KEY_EX1REPS2, mEx1Reps2);
cvUpdate.put(KEY_EX1REPS3, mEx1Reps3);
ourDatabase.update(DATABASE_TABLE, cvUpdate, KEY_ROWID + "=" + lRow, null);
}
public void deleteEntry(long lRow1) throws SQLException{
// TODO Auto-generated method stub
ourDatabase.delete(DATABASE_TABLE, KEY_ROWID + "=" + lRow1, null);
}
public static String convertArrayToString(String[] array){
String str = "";
for (int i = 0;i<array.length; i++) {
str = str+array[i];
// Do not append comma at the end of last element
if(i<array.length-1){
str = str+",";
}
}
return str;
}
public static String[] convertStringToArray(String str){
String[] arr = str.split(",");
return arr;
}
public void deleteAll() {
Cursor c = getAllRows();
long rowId = c.getColumnIndexOrThrow(KEY_ROWID);
if (c.moveToFirst()) {
do {
deleteRow(c.getLong((int) rowId));
} while (c.moveToNext());
}
c.close();
}
public Cursor getAllRows() {
String where = null;
Cursor c = ourDatabase.query(true, DATABASE_TABLE, ALL_KEYS,
where, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
public boolean deleteRow(long rowId) {
String where = KEY_ROWID + "=" + rowId;
return ourDatabase.delete(DATABASE_TABLE, where, null) != 0;
}
}