Question

我为数据库表的名称创建了这个类：

public class TableDatas {
    public TableDatas() {
    }
    public static abstract class TableInfo implements BaseColumns//columns of tables
    {
        public static final String first_Name = "first_name" ;
        public static final String last_Name = "last_name" ;
        public static final String sex  = "sex" ;
        public static final String birth_date = "birth_date" ;
        public static final String db_name = "UserInfo" ;
        public static final String tbl_name = "UserData" ;

    }

}

在db helper类中我创建了一个游标函数：

    public Cursor getInfo(DatabaseOperat dop) {
            SQLiteDatabase sq = dop.getReadableDatabase();
            String columns[] = {TableInfo.first_Name, TableInfo.last_Name, TableInfo.sex, TableInfo.birth_date};
            Cursor CR = sq.query(TableInfo.tbl_name, columns, null, null, null, null, null);
            return CR;
        }

在mainActivity中，我这样做是为了保存数组列表中列的数据：

 DatabaseOperat DOP = new DatabaseOperat(CTX);
        Cursor CR = DOP.getInfo(DOP);
        DOP.getWritableDatabase();
        CR.moveToFirst();
        while (!CR.isAfterLast()) {


            Fnames.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.first_Name)));
            Lnames.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.last_Name)));
            Birthdates.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.sex)));
            Sex.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.birth_date)));
            // Adding contact to list

        }
            CR.close();
            Toast.makeText(getApplicationContext(), "Cursor Success", Toast.LENGTH_LONG).show();

获取中的错误如下：

android.database.sqlite.SQLiteException：...没有这样的列：first_name（代码1）:,同时编译：SELECT first_name，last_name，sex，birth_date FROM UserData 任何错误在哪里？

Answer 1

更改此代码：

DatabaseOperat DOP = new DatabaseOperat(CTX);
    Cursor CR = DOP.getInfo(DOP);
    DOP.getWritableDatabase();
    CR.moveToFirst();
    while (!CR.isAfterLast()) {


        Fnames.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.first_Name)));
        Lnames.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.last_Name)));
        Birthdates.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.sex)));
        Sex.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.birth_date)));
        // Adding contact to list

    }
        CR.close();
        Toast.makeText(getApplicationContext(), "Cursor Success", Toast.LENGTH_LONG).show();

致：

DatabaseOperat DOP = new DatabaseOperat(CTX);
    DOP.getWritableDatabase();        
    Cursor CR = DOP.getInfo(DOP);
    CR.moveToFirst();
    while (!CR.isAfterLast()) {


        Fnames.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.first_Name)));
        Lnames.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.last_Name)));
        Birthdates.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.sex)));
        Sex.add(CR.getString(CR.getColumnIndex(TableDatas.TableInfo.birth_date)));
        // Adding contact to list

    }
        CR.close();
        Toast.makeText(getApplicationContext(), "Cursor Success", Toast.LENGTH_LONG).show();

首先调用getWritableDatabase（）而不是getInfo（）

错误：android.database.sqlite.SQLiteException：没有这样的列：first_name（代码1）

1 个答案: