在我当前的应用程序中，有一个SQLite数据库正在按预期运行。但是我想在数据库中添加一个日期列。
如何将此列添加到下面的DatabaseHelper类中？
DatabaseHelper类：
public class DatabaseHelper extends SQLiteOpenHelper {
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "MultapplyDatabase";
// Contacts table name
private static final String TABLE_SCORE = "scores";
// Contacts Table Columns names
private static final String COL_NAME = "name";
private static final String COL_SCORE = "score";
/**
* Constructor
* @param context
*/
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
/**
* Method that creates the database
*/
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_TABLE_SCORE = "CREATE TABLE " + TABLE_SCORE + "("
+ COL_NAME + " STRING PRIMARY KEY," + COL_SCORE + " INTEGER" + ")";
db.execSQL(CREATE_TABLE_SCORE);
}
/**
* Method that upgrades the database
*/
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_SCORE);
// Create tables again
onCreate(db);
}
/**
* All CRUD operations
*/
// Adding new score details (Name, score, date)
void addScore(Score score) {
SQLiteDatabase db = this.getWritableDatabase();
//ContentValues- holds the values.
ContentValues values = new ContentValues();
values.put(COL_NAME, score.getName()); // Contact Name
values.put(COL_SCORE, score.getScore()); // Contact Phone
// Inserting Row (i.e. the values that were entered from above
db.insert(TABLE_SCORE, null, values);
db.close(); // Closing database connection
}
/**
* Method will return a single Name and score
* @param id
* @return
*/
// Getting single contact
Score getScore(String name) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_SCORE, new String[] { COL_NAME,
COL_SCORE}, COL_NAME + "=?",
new String[] { String.valueOf(name) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Score score = new Score(cursor.getString(0),Integer.parseInt(cursor.getString(1)));
// return contact
return score;
}
/**
* Method will return a list of all the scores
* @return
*/
// Getting All Contacts
public List<Score> getAllScores() {
List<Score> scoreList = new ArrayList<Score>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_SCORE;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Score score = new Score();
score.setName(cursor.getString(0));
score.setScore(Integer.parseInt(cursor.getString(1)));
// Adding contact to list
scoreList.add(score);
} while (cursor.moveToNext());
}
// return contact list
return scoreList;
}
}
以下代码是将数据写入数据库的代码部分。
即。添加了一个Score对象，其中包含Name和Score列。在这里，我还想在我添加到数据库的Date列中添加数据创建日期。我该怎么做？
/**
* CRUD Operations
* */
// Inserting Contacts
Log.d("Insert: ", "Inserting ..");
db.addScore(new Score(UserName.getUserName(), score));
// Reading all contacts
Log.d("Reading: ", "Reading all contacts..");
List<Score> scores = db.getAllScores();
for (Score s : scores) {
String log = "Name: " + s.getName() + " ,Score: " + s.getScore();
// Writing Contacts to log
Log.d("Name: ", log);
}
更新：
现在收到以下错误：
07-02 21:31:44.785: E/SQLiteLog(2757): (1) table scores has no column named date
07-02 21:31:44.785: E/SQLiteDatabase(2757): Error inserting score=4 date=1404336704680 name=RooosYoungKen
07-02 21:31:44.785: E/SQLiteDatabase(2757): at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
尝试使用以下内容实现日期时：
public class DatabaseHelper extends SQLiteOpenHelper {
// Database Version
private static final int DATABASE_VERSION = 2;
// Database Name
private static final String DATABASE_NAME = "MultapplyDatabase";
// Contacts table name
private static final String TABLE_SCORE = "scores";
// Contacts Table Columns names
private static final String COL_NAME = "name";
private static final String COL_SCORE = "score";
private static final String COL_DATE = "date";
/**
* Constructor
* @param context
*/
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
/**
* Method that creates the database
*/
@Override
public void onCreate(SQLiteDatabase db) {
//NOTE: may need to alter the below to take out everything after INTEGER
String CREATE_TABLE_SCORE = "CREATE TABLE " + TABLE_SCORE + "("
+ COL_NAME + " STRING PRIMARY KEY," + COL_SCORE + " INTEGER" + COL_DATE + "LONG" + ")";
db.execSQL(CREATE_TABLE_SCORE);
}
/**
* Method that upgrades the database
*/
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_SCORE);
// Create tables again
onCreate(db);
}
/**
* All CRUD operations
*/
// Adding new score details (Name, score, date)
void addScore(Score score) {
SQLiteDatabase db = this.getWritableDatabase();
//ContentValues- holds the values.
ContentValues values = new ContentValues();
values.put(COL_NAME, score.getName());
values.put(COL_SCORE, score.getScore());
values.put(COL_DATE, score.getDate());
// Inserting Row (i.e. the values that were entered from above
db.insert(TABLE_SCORE, null, values);
db.close(); // Closing database connection
}
/**
* Method will return a single Name and score
* @param id
* @return
*/
// Getting single contact
Score getScore(String name) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_SCORE, new String[] { COL_NAME,
COL_SCORE, COL_DATE}, COL_NAME + "=?",
new String[] { String.valueOf(name) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Score score = new Score(cursor.getString(0),Integer.parseInt(cursor.getString(1)),cursor.getLong(2));
// return contact
return score;
}
/**
* Method will return a list of all the scores
* @return
*/
// Getting All Contacts
public List<Score> getAllScores() {
List<Score> scoreList = new ArrayList<Score>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_SCORE;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Score score = new Score();
score.setName(cursor.getString(0));
score.setScore(Integer.parseInt(cursor.getString(1)));
score.setDate(cursor.getLong(2));
// Adding contact to list
scoreList.add(score);
} while (cursor.moveToNext());
}
// return contact list
return scoreList;
}
}
和其他班级一样：
/ ** * CRUD操作 * * / //插入联系人 Log.d（＆＃34; Insert：＆＃34;，＆＃34; Inserting ..＆＃34;）; db.addScore（new Score（UserName.getUserName（），score，System.currentTimeMillis（）））; //需要在这里添加日期
// Reading all contacts
Log.d("Reading: ", "Reading all contacts..");
List<Score> scores = db.getAllScores();
for (Score s : scores) {
String log = "Name: " + s.getName() + " ,Score: " + s.getScore() + "Date: " + s.getDate();
// Writing Contacts to log
Log.d("Name: ", log);
}
}
答案 0 :(得分：0)
请看这个链接：
http://www.sqlite.org/datatype3.html
不幸的是，SQLite没有DATE类型，但是我建议将当前时间转换为带有long的{{1}}，将该值作为REAL或LONG插入到sqlite表中。如果要检索它，可以使用long dbLong = System.currentTimeMillis()