我最近完成了我的数据库代码并正常工作，但随后我根据需要添加了注释。几天后，我再次尝试运行我的代码，但数据库现在崩溃了，之前它运行良好，但我不知道出了什么问题。
日志猫错误是
09-11 01:36:55.414: E/AndroidRuntime(20188): Caused by: android.database.sqlite.SQLiteException: near "comments": syntax error (code 1): , while compile: ALTER TABLE 添加了注释和修复代码;
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;
/**
* The database adapter which controls the uses of the database
* Uses various methods in the operation of the database
* @author Michael
*
*/
public class DatabaseAdapter {
//Initialise the static fields
static final String KEY_ROWID = "_id";
static final String KEY_NAME = "name";
static final String KEY_EMAIL = "email";
static final String KEY_LNAME = "lname";
static final String KEY_GENDER = "gender";
static final String KEY_DATE = "date";
static final String KEY_HOBBIES = "hobbies";
static final String TAG = "DBAdapter";
static final String DATABASE_NAME = "MyDB";
static final String DATABASE_TABLE = "famous people";
//The database version, MUST INCREMENT AFTER CHANGE
static final int DATABASE_VERSION = 16;
static final String DATABASE_CREATE =
"create table contacts (_id integer primary key autoincrement, "
+ "name text not null, lname text not null, gender not null, date not null, hobbies not null);";
final Context context;
//Create the database helper
DatabaseHelper DBHelper;
//Create the SQLiteDatabase with db
SQLiteDatabase db;
/**
* The constructor for the databaseadapter
* @param ctx
*/
public DatabaseAdapter(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
/**
* The database helper which extends the SQLiteOpenHelper
*/
private static class DatabaseHelper extends SQLiteOpenHelper
{
//The database helper uses context
DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
/**
* On creation of the database, attempt to create the database
*/
public void onCreate(SQLiteDatabase db)
{
try {
db.execSQL(DATABASE_CREATE);
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
/**
* When the database version changes
*/
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
//Use an if loop to check the version
if (oldVersion < newVersion){
//Input what has been changed
final String ALTER_TBL = "ALTER TABLE added comments and fix code;";
//Call the execSQL with the ALTER_TBL string
db.execSQL(ALTER_TBL);
} else {
//Log an error that the update did not work
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
//Execute the execSQL with string
db.execSQL("DROP TABLE IF EXISTS contacts");
//Create a new database
onCreate(db);
}
}
}
/**
* Open the database using Database helper
* @return
* @throws SQLException
*/
public DatabaseAdapter open() throws SQLException
{
//Use the writable database method
db = DBHelper.getWritableDatabase();
return this;
}
/**
* Close the database using Database helper
*/
public void close()
{
//Close the database
DBHelper.close();
}
/**
* Insert a contact into the database
* @param name, lname, gender, date, hobbies
* @return
*/
public long insertContact(String name, String lname, String gender, String date, String hobbies)
{
//Create new initial Values
ContentValues initialValues = new ContentValues();
//Use the put method to put in the first name
initialValues.put(KEY_NAME, name);
//Use the put method to put in the last name
initialValues.put(KEY_LNAME, lname);
//Use the put method to put in the gender
initialValues.put(KEY_GENDER, gender);
//Use the put method to put in the date of birth
initialValues.put(KEY_DATE, date);
//Use the put method to put in the hobbies
initialValues.put(KEY_HOBBIES, hobbies);
//insert the initial values into the database table
return db.insert(DATABASE_TABLE, null, initialValues);
}
/**
* Delete a contact
* @param rowId
* @return
*/
public boolean deleteContact(long rowId)
{
//Delete the item at rowId
return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}
/**
* Get all the contacts in the database
* @return
*/
public Cursor getAllContacts()
{
return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_NAME,
KEY_LNAME, KEY_GENDER, KEY_DATE, KEY_HOBBIES}, null, null, null, null, null);
}
/**
* Shows the database item at particular rowId
* @param rowId
* @return
* @throws SQLException
*/
public Cursor getContact(long rowId) throws SQLException
{
Cursor mCursor =
db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
KEY_NAME, KEY_LNAME, KEY_GENDER, KEY_DATE, KEY_HOBBIES}, KEY_ROWID + "=" + rowId, null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
/**
* Update the contact with new values
* @param rowId, name, lname, gender, date, hobbies
* @return
*/
public boolean updateContact(long rowId, String name, String lname, String gender, String date, String hobbies)
{
//Create new content values set as args
ContentValues args = new ContentValues();
//Put in the new name
args.put(KEY_NAME, name);
//Put in the new last name
args.put(KEY_LNAME, lname);
//Put in the new gender
args.put(KEY_GENDER, gender);
//Put in the new date
args.put(KEY_DATE, date);
//Put in the new hobby
args.put(KEY_HOBBIES, hobbies);
//Call the update method and udate the database
return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}
}