我是android中sqllite的新手。我正在向sql数据库添加记录，insert和select查询都没有给出运行时错误，除了我在获取数据时有空光标（在Select Query上）。如果在插入值或获取值时出现问题，请告诉我。与选择查询一样，我得到列名但没有记录。 这是我的代码。
public class SQLHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "MyDb.db";
private static final int DATABASE_VERSION = 1;
private SQLiteDatabase database;
public String stringArray[];
private ArrayList<tasksList> arrayList;
public final static String PROCESS_TABLE = "Process";
public final static String DB_P_ID = "db_process_id";
public final static String PROCESS_ASSIGNMENT_ID = "process_id";
public final static String CASETITLE = "case_title";
public final static String APPEARANCE_DATE = "appearance_date";
public final static String APPEARANCE_TIME = "appearance_time";
public final static String APPEARANCE_REASON = "appearance_reason";
public final static String COURT_NAME = "court_name";
public final static String RESPONDENT_NAME = "respondent_name";
public final static String ADDRESS = "address";
public final static String CONTACT_NO = "contact_no";
public final static String CNIC = "cnic";
public final static String NOTICE_NUMBER = "notice_number";
private static final String DATABASE_CREATE_PROCESS_TABLE = " CREATE TABLE "+ PROCESS_TABLE + " (db_process_id integer primary key autoincrement," +
" process_id text not null," +
" case_title text not null,appearanc e_date text not null ,appearance_time text not null, court_name text not null , respondent_name text not null ," +
" address text not null ,contact_no text not null ,cnic text not null , appearance_reason text not null , notice_number text not null );";
public SQLHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL(DATABASE_CREATE_PROCESS_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
Log.w(SQLHelper.class.getName(),"Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS Process");
onCreate(sqLiteDatabase);
}
public Boolean insertProcess(String id, String case_Title,String app_date, String app_time, String app_reason,
String court_name,String name,String location,String cnic,String notice_no,String contact_no) {
database = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(PROCESS_ASSIGNMENT_ID, id);
values.put(CASETITLE, case_Title);
values.put(APPEARANCE_DATE, app_date);
values.put(APPEARANCE_TIME, app_time);
values.put(APPEARANCE_REASON, app_reason);
values.put(COURT_NAME, court_name);
values.put(RESPONDENT_NAME, name);
values.put(ADDRESS, location);
values.put(CONTACT_NO, contact_no);
values.put(CNIC, cnic);
values.put(NOTICE_NUMBER, notice_no);
database.insert(PROCESS_TABLE, null, values);
return true;
}
public Cursor getCompletedTask(Context applicationContext) {
Context context = applicationContext;
database = this.getReadableDatabase();
String[] cols = new String[] { CASETITLE};
Cursor mCursor = database.rawQuery(" Select * from " + PROCESS_TABLE , null);
// Cursor mCursor = database.query(true, PROCESS_TABLE, cols, null, null, null, null, null, null);
int size = mCursor.getCount();
stringArray = new String[size];
if (mCursor != null) {
mCursor.moveToFirst();
while (!mCursor.isAfterLast()) {
String id = mCursor.getString(0);
String title = mCursor.getString(1);
tasksList fooditem=new tasksList();
fooditem.setCase_id(id);
fooditem.setCase_title(title);
arrayList.add(fooditem);
mCursor.moveToNext();
}
}
return mCursor; // iterate to get each value.
}
答案 0 :(得分：0)
您的问题是 appearanc e_date text not null 中有空格，即这应该是 appearance_date text not null
说这本身不会导致失败，只是列名称将是 appearanc 而不是appearance_date。这很可能会导致 随之而来的混淆（例如您可能发生的问题如下）。
这是为什么建议依赖单个源表和列名的一个主要示例。因此，而不是纠正： -
private static final String DATABASE_CREATE_PROCESS_TABLE = " CREATE TABLE "+ PROCESS_TABLE + " (db_process_id integer primary key autoincrement," +
" process_id text not null," +
" case_title text not null,appearance_date text not null ,appearance_time text not null, court_name text not null , respondent_name text not null ," +
" address text not null ,contact_no text not null ,cnic text not null , appearance_reason text not null , notice_number text not null );";
我建议如下： -
private static final String CREATE_PROCESS_TABLE =
"CREATE TABLE IF NOT EXISTS " +
PROCESS_TABLE +
"(" +
PROCESS_ASSIGNMENT_ID + " INTEGER PRIMARY KEY," + //NOTE you very likely don't want autoincrement
CASETITLE + " TEXT NOT NULL," +
APPEARANCE_DATE + " TEXT NOT NULL," +
APPEARANCE_TIME + " TEXT NOt NULL," +
COURT_NAME + " TEXT NOT NULL, " +
RESPONDENT_NAME + " TEXT NOT NULL," +
ADDRESS + " TEXT NOT NULL," +
CONTACT_NO + " TEXT NOT NULL, " +
CNIC + " TEXT NOT NULL," +
APPEARANCE_REASON + " TEXT NOT NULL," +
NOTICE_NUMBER + " TEXT NOT NULL" +
")";
您的问题可能是由于非预期的列名称 appearan 而非预期的 appearance_date 列名称导致的插入记录不会知道列 appearance_date 而不插入行。所以你的桌子将是空的。
如果您查看日志，您会看到类似于： -
的内容05-07 21:13:54.724 1285-1285/? E/SQLiteLog: (1) table Process has no column named appearance_date
如上所述进行更正（删除不需要的空间），删除应用程序的数据，然后重新运行应用程序应该纠正该问题。
答案 1 :(得分：-2)
为插入数据和反向数据制作模型类..
试试这段代码..
public class DBHelper extends SQLiteOpenHelper{
//USER TABLE
public static final String USER_TABLE_NAME = "MyTableTwo";
public static final String USER_COLUMN_USER_ID = "id";
public static final String USER_COLUMN_USER_NAME = "Item_Name";
public static final String USER_COLUMN_USER_ADDRESS = "Weight";
public static final String USER_COLUMN_USER_CREATED_AT = "MRP";
public static final String USER_COLUMN_USER_UPDATED_AT = "BARCODE";
public DBHelper(Context context,
String dbName,
Integer version) {
super(context, dbName, null, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
tableCreateStatements(db);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + USER_TABLE_NAME);
onCreate(db);
}
private void tableCreateStatements(SQLiteDatabase db) {
try {
db.execSQL(
"CREATE TABLE IF NOT EXISTS "
+ USER_TABLE_NAME + "("
+ USER_COLUMN_USER_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ USER_COLUMN_USER_NAME + " VARCHAR(20), "
+ USER_COLUMN_USER_ADDRESS + " VARCHAR(50), "
+ USER_COLUMN_USER_CREATED_AT + " VARCHAR(10) DEFAULT " + getCurrentTimeStamp() + ", "
+ USER_COLUMN_USER_UPDATED_AT + " VARCHAR(10) DEFAULT " + getCurrentTimeStamp() + ")"
);
} catch (SQLException e) {
e.printStackTrace();
}
}
public List<MyTableTwo> getMyItems() {
List<MyTableTwo> mySuperList = new ArrayList<>();
SQLiteDatabase db = this.getReadableDatabase();
String selectQuery = "SELECT * FROM " + USER_TABLE_NAME ;
Cursor c = db.rawQuery(selectQuery, null);
if (c != null) {
c.moveToFirst();
while (c.isAfterLast() == false) {
MyTableTwo myTable = new MyTableTwo();
myTable.itemName = (c.getString(c.getColumnIndex("Item_Name")));
myTable.weight = (c.getString(c.getColumnIndex("Weight")));
myTable.mrp = (c.getString(c.getColumnIndex("MRP")));
myTable.barcod = (c.getString(c.getColumnIndex("BARCODE")));
mySuperList.add(myTable);
c.moveToNext();
}
}
return mySuperList;
}
public Long insertUser(MyTableTwo user) throws Exception {
try {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(USER_COLUMN_USER_NAME, user.itemName);
contentValues.put(USER_COLUMN_USER_ADDRESS, user.barcod);
contentValues.put(USER_COLUMN_USER_CREATED_AT, user.weight);
contentValues.put(USER_COLUMN_USER_UPDATED_AT, user.barcod);
return db.insert(USER_TABLE_NAME, null, contentValues);
} catch (Exception e) {
e.printStackTrace();
throw e;
}
}
private String getCurrentTimeStamp() {
return String.valueOf(System.currentTimeMillis() / 1000);
}
}
和actvity使用如下。
DBHelper dbHelper=new DBHelper(DbInsert.this,"DB",1);
MyTableTwo myTableTwo=new MyTableTwo("abcd","5kg","120","xyz");
try {
dbHelper.insertUser(myTableTwo);
} catch (Exception e) {
e.printStackTrace();
}
pojo class ..
public class MyTableTwo {
public String itemName,weight,mrp,barcod;
public MyTableTwo(){}
public MyTableTwo(String itemName, String weight, String mrp, String barcod) {
this.itemName = itemName;
this.weight = weight;
this.mrp = mrp;
this.barcod = barcod;
}
}
你也做了getter setter方法..