收到类似“您的应用程序意外停止，请再次尝试强制关闭"之类的错误消息.

问题描述

我已经完成了android数据库，但在控制台上出现错误，例如"您的应用程序意外停止.请再次尝试强制关闭"
这是我的代码:

I have done android database but error on console like "your appliction has stoped unexpectdly .try again force close"
This is my code:

package mina.android.DatabaseDemo;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHelper extends SQLiteOpenHelper {
	static final String dbName="demoDB";
	static final String employeeTable="Employees";
	static final String colID="EmployeeID";
	static final String colName="EmployeeName";
	static final String colAge="Age";
	static final String colDept="Dept";

	static final String deptTable="Dept";
	static final String colDeptID="DeptID";
	static final String colDeptName="DeptName";

	static final String viewEmps="ViewEmps";
	public DatabaseHelper(Context context) {
		super(context, dbName, null,33);

		// TODO Auto-generated constructor stub
	}
	@Override
	public void onCreate(SQLiteDatabase db) {
		// TODO Auto-generated method stub

		db.execSQL("CREATE TABLE "+deptTable+" ("+colDeptID+ " INTEGER PRIMARY KEY , "+
				colDeptName+ " TEXT)");

		db.execSQL("CREATE TABLE "+employeeTable+" ("+colID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+
				colName+" TEXT, "+colAge+" Integer, "+colDept+" INTEGER NOT NULL ,FOREIGN KEY ("+colDept+") REFERENCES "+deptTable+" ("+colDeptID+"));");


		db.execSQL("CREATE TRIGGER fk_empdept_deptid " +
				" BEFORE INSERT "+
				" ON "+employeeTable+

				" FOR EACH ROW BEGIN"+
				" SELECT CASE WHEN ((SELECT "+colDeptID+" FROM "+deptTable+" WHERE "+colDeptID+"=new."+colDept+" ) IS NULL)"+
				" THEN RAISE (ABORT,'Foreign Key Violation') END;"+
				"  END;");

		db.execSQL("CREATE VIEW "+viewEmps+
				" AS SELECT "+employeeTable+"."+colID+" AS _id,"+
				" "+employeeTable+"."+colName+","+
				" "+employeeTable+"."+colAge+","+
				" "+deptTable+"."+colDeptName+""+
				" FROM "+employeeTable+" JOIN "+deptTable+
				" ON "+employeeTable+"."+colDept+" ="+deptTable+"."+colDeptID
				);
		//Inserts pre-defined departments
		InsertDepts(db);
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		// TODO Auto-generated method stub

		db.execSQL("DROP TABLE IF EXISTS "+employeeTable);
		db.execSQL("DROP TABLE IF EXISTS "+deptTable);

		db.execSQL("DROP TRIGGER IF EXISTS dept_id_trigger");
		db.execSQL("DROP TRIGGER IF EXISTS dept_id_trigger22");
		db.execSQL("DROP TRIGGER IF EXISTS fk_empdept_deptid");
		db.execSQL("DROP VIEW IF EXISTS "+viewEmps);
		onCreate(db);
	}

	 void AddEmployee(Employee emp)
	{


		 SQLiteDatabase db= this.getWritableDatabase();


		ContentValues cv=new ContentValues();

		cv.put(colName, emp.getName());
		cv.put(colAge, emp.getAge());
		cv.put(colDept, emp.getDept());
		//cv.put(colDept,2);

		db.insert(employeeTable, colName, cv);
		db.close();


	}

	 int getEmployeeCount()
	 {
		SQLiteDatabase db=this.getWritableDatabase();
		Cursor cur= db.rawQuery("Select * from "+employeeTable, null);
		int x= cur.getCount();
		cur.close();
		return x;
	 }

	 Cursor getAllEmployees()
	 {
		 SQLiteDatabase db=this.getWritableDatabase();



		 //Cursor cur= db.rawQuery("Select "+colID+" as _id , "+colName+", "+colAge+" from "+employeeTable, new String [] {});
		 Cursor cur= db.rawQuery("SELECT * FROM "+viewEmps,null);
		 return cur;

	 }

	 Cursor getAllDepts()
	 {
		 SQLiteDatabase db=this.getReadableDatabase();
		 Cursor cur=db.rawQuery("SELECT "+colDeptID+" as _id, "+colDeptName+" from "+deptTable,new String [] {});

		 return cur;
	 }

	 void InsertDepts(SQLiteDatabase db)
	 {
		 ContentValues cv=new ContentValues();
			cv.put(colDeptID, 1);
			cv.put(colDeptName, "Sales");
			db.insert(deptTable, colDeptID, cv);
			cv.put(colDeptID, 2);
			cv.put(colDeptName, "IT");
			db.insert(deptTable, colDeptID, cv);
			cv.put(colDeptID, 3);
			cv.put(colDeptName, "HR");
			db.insert(deptTable, colDeptID, cv);
			db.insert(deptTable, colDeptID, cv);

	 }

	 public String GetDept(int ID)
	 {
		 SQLiteDatabase db=this.getReadableDatabase();

		 String[] params=new String[]{String.valueOf(ID)};
		 Cursor c=db.rawQuery("SELECT "+colDeptName+" FROM"+ deptTable+" WHERE "+colDeptID+"=?",params);
		 c.moveToFirst();
		 int index= c.getColumnIndex(colDeptName);
		 return c.getString(index);
	 }

	 public Cursor getEmpByDept(String Dept)
	 {
		 SQLiteDatabase db=this.getReadableDatabase();
		 String [] columns=new String[]{"_id",colName,colAge,colDeptName};
		 Cursor c=db.query(viewEmps, columns, colDeptName+"=?", new String[]{Dept}, null, null, null);
		 return c;
	 }

	 public int GetDeptID(String Dept)
	 {
		 SQLiteDatabase db=this.getReadableDatabase();
		 Cursor c=db.query(deptTable, new String[]{colDeptID+" as _id",colDeptName},colDeptName+"=?", new String[]{Dept}, null, null, null);
		 //Cursor c=db.rawQuery("SELECT "+colDeptID+" as _id FROM "+deptTable+" WHERE "+colDeptName+"=?", new String []{Dept});
		 c.moveToFirst();
		 return c.getInt(c.getColumnIndex("_id"));

		 }

	 public int UpdateEmp(Employee emp)
	 {
		 SQLiteDatabase db=this.getWritableDatabase();
		 ContentValues cv=new ContentValues();
		 cv.put(colName, emp.getName());
		 cv.put(colAge, ( emp).getAge());
		 cv.put(colDept, emp.getDept());
		 return db.update(employeeTable, cv, colID+"=?", new String []{String.valueOf(emp.getID())});

	 }

	 public void DeleteEmp(Employee emp)
	 {
		 SQLiteDatabase db=this.getWritableDatabase();
		 db.delete(employeeTable,colID+"=?", new String [] {String.valueOf(emp.getID())});
		 db.close();
	 }
}

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