Android：如何编写我们自己的类而不是使用sugar ORM

我有五个类，每个类都有不同的字段名。我正在通过扩展SugarRecord来存储和检索所有值。但是我想扩展我的课程而不是SugarRecord。我不知道如何为所有模态类编写公共类。我需要一些从哪里开始编写代码的指导。在这里，我发布了试图插入和检索的模态类。请帮帮我。提前谢谢

作业班

public class assignments extends SugarRecord<assignments> {
public String valid;
public String pid;
public String event_added;
public String eid;
public String nature_of_contact;
public String assignment_date;
public String status;
public String aid;
public assignments(Context arg0) {
    super(arg0);
    // TODO Auto-generated constructor stub
}
}

public class Requirement extends SugarRecord<Requirement> {
public String rid;
public String pid;
public String wid;
public String name;
public Requirement(Context arg0) {
    super(arg0);
    // TODO Auto-generated constructor stub
}
@Override
public String toString() {
    // TODO Auto-generated method stub
    return this.name;
}
}

在DBHelper类中，我插入DayExpensesDB类的所有值。 这是我的DBHelper类

public class DBHelper {
SQLiteDatabase db;
DayExpensesDB dedb;
public DBHelper(Context context)
{
    dedb = new DayExpensesDB(context);
}
public SQLiteDatabase open()
{
    return dedb.getWritableDatabase();
}
public void close()
{
    dedb.close();
}
public void insertValues(double enter, double food, double medicine, double travel, double total, String date)
{
    db = this.open();
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd"); 
    date = dateFormat.format(new Date());
    ContentValues values = new ContentValues();
    values.put(DayExpensesDB.ENTERTAINMENT, enter);
    values.put(DayExpensesDB.FOOD, food);
    values.put(DayExpensesDB.MEDICINE, medicine);
    values.put(DayExpensesDB.TRAVEL, travel);
    values.put(DayExpensesDB.TOTAL, total);
    values.put(DayExpensesDB.DATEVALUE, date);
    db.insert(DayExpensesDB.TABLE_NAME, null, values);
    this.close();
}
public ArrayList<String> getValues()
{
    ArrayList<String> names = new ArrayList<String>();
    db = this.open();
    String query = "select * from "+DayExpensesDB.TABLE_NAME;
    Cursor cursor = db.rawQuery(query, null);
    if(cursor.moveToFirst())
    {
        do{
            names.add(cursor.getString(cursor.getColumnIndex(DayExpensesDB.ENTERTAINMENT)));
            names.add(cursor.getString(cursor.getColumnIndex(DayExpensesDB.FOOD)));
            names.add(cursor.getString(cursor.getColumnIndex(DayExpensesDB.MEDICINE)));
            names.add(cursor.getString(cursor.getColumnIndex(DayExpensesDB.TRAVEL)));
            names.add(cursor.getString(cursor.getColumnIndex(DayExpensesDB.DATEVALUE)));;
            names.add(cursor.getString(cursor.getColumnIndex(DayExpensesDB.TOTAL)));;
            names.add(cursor.getString(cursor.getColumnIndex(DayExpensesDB.TOTAL)));;
            //names.add(cursor.get)
        }while(cursor.moveToNext());
    }
    return names;

}

公共类DBHelper{
sqlitedb数据库；
日费用d b d b；
公共DBHelper（上下文）
{
dedb=新的日支出SDB（上下文）；
}
公共SQLiteDatabase open（）
{
返回dedb.getWritableDatabase（）；
}
公众假期结束（）
{
dedb.close（）；
}
public void insertValues（双输入、双食物、双药物、双旅行、双总计、字符串日期）
{
db=this.open（）；
SimpleDataFormat dateFormat=新SimpleDataFormat（“yyyy-MM-dd”）；
date=dateFormat.format（新日期（））；
ContentValues=新的ContentValues（）；
value.put（DayExpensesDB.ENTERTAINMENT，输入）；
价值。投入（日支出b.食品、食品）；
价值。投入（日支出b.医药、医药）；
价值。投入（日支出b.差旅、差旅）；
价值。投入（日支出总额、总额）；
value.put（daycexpensesdb.DATEVALUE，date）；
db.insert（daycexpensesdb.TABLE_NAME，null，value）；
这个。关闭（）；
}
公共ArrayList getValues（）
{
ArrayList name=新的ArrayList（）；
db=this.open（）；
String query=“select*from”+daycexpensesdb.TABLE\u名称；
Cursor Cursor=db.rawQuery（查询，空）；
if（cursor.moveToFirst（））
{
做{
add（cursor.getString（cursor.getColumnIndex（DayExpensesDB.ENTERTAINMENT））；
add（cursor.getString（cursor.getColumnIndex（DayExpensesDB.FOOD））；
add（cursor.getString（cursor.getColumnIndex（DayExpensesDB.MEDICINE））；
add（cursor.getString（cursor.getColumnIndex（DayExpensesDB.TRAVEL））；
add（cursor.getString（cursor.getColumnIndex（DayExpensesDB.DATEVALUE））；；
add（cursor.getString（cursor.getColumnIndex（DayExpensesDB.TOTAL））；；
add（cursor.getString（cursor.getColumnIndex（DayExpensesDB.TOTAL））；；
//name.add（cursor.get）
}while（cursor.moveToNext（））；
}
返回姓名；
}

---

因此，如果我遵循上述编码，那么我需要为每个模式类（如分配类和需求类）编写单独的DBHelper类。但我想编写一个通用类，该类应该执行插入、保存和检索操作。

不确定我是否理解，但下面是我要做的。
我会创建一个非常好的结构
首先，我首先会从你的类DayExpensesDB中删除你放在那里的所有东西，成员。相反，我会用脚本创建我的数据库，所有东西都是OOP风格的。 例如，您为包含有关列的内容的列创建了一个类，它是主键，是或不是？它是唯一的还是不唯一的？

编辑
添加了从pastebin中删除的代码

//类，该类描述数据库列。

public class DatabaseColumnImpl implements DatabaseColumn {

    private boolean uniqueField = false;

    private boolean autoIncrement = false;

    private boolean isForeignKey = false;

    private boolean primaryKey = false;

    private String rowName;
    private RowType dataRowType;

     public GenericColumnImpl(boolean primaryKey, boolean autoIncrement, boolean uniqueField, boolean isForeignKey, String fieldName, @NonNull RowType type) {
        this.uniqueField = uniqueField;
        this.primaryKey = primaryKey;
        this.autoIncrement = autoIncrement;
        this.dataRowType = type;
        this.rowName = fieldName;
        this.isForeignKey = isForeignKey;
     }

     public DatabaseColumnImpl(boolean primaryKey, boolean autoIncrement, String fieldName, @NonNull RowType type) {
         this(primaryKey, autoIncrement, false, false, fieldName, type);
     }
    //... setters and getters
}

接下来，我将定义我的数据库契约和要插入的行。例如，您的表要求有4-5列，但尚未知道行（请参见下图）。

//每行的数据库列。

  public enum DatabaseTable{

    DATA(new DatabaseColumnImpl(true, true, DataContract.X._ID, SqliteDataType.Integer),
        new DatabaseColumnImpl(DataContract.X.TIMEDURATION, SqliteDataType.Integer),
        new DatabaseColumnImpl(DataContract.X.DESCRIPTION, SqliteDataType.String),
        new DatabaseColumnImpl(DataContract.X.NAME, SqliteDataType.String));
  //much more data can be added here
   private DatabaseColumnImpl[] genericColumns;

   private DatabaseTable(DatabaseColumnImpl... columns) {
       this.genericColumns = columns;
   }

   public DatabaseColumnImpl[] getColumns() {
       return genericColumns;
   }

   public String getName() {
      return this.name();
   }
}

完成这些之后，我将创建数据库契约类

public class DatabaseContract {
    public static final String CONTENT_STRING = "content://";

    public static final String CONTENT_AUTHORITY = "com.org.data";

    public static final String VND_AUTHORITY = "vnd.org.data";

    public static final Uri BASE_CONTENT_URI = Uri.parse(CONTENT_STRING + CONTENT_AUTHORITY);


    public static final class XData implements BaseColumns {

         public static final String TABLE_NAME = "xdata";

         //content://com.org.data/xdata
         public static final Uri CONTENT_URI = BASE_CONTENT_URI.buildUpon().appendPath(TABLE_NAME).build();

         //vnd.android.cursor.dir/vnd.org.data
         public static final String CONTENT_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE + File.separator + VND_AUTHORITY;

         //vnd.android.cursor.item/vnd.org.data
         public static final String CONTENT_ITEMTYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + File.separator + VND_AUTHORITY;

         public static final String NAME = "name";

         public static final String DESCRIPTION = "description";

         public static final String TIMEDURATION = "time_duration";
         //more data

    public static Uri buildXdataUri(long id) {
        return ContentUris.withAppendedId(CONTENT_URI, id);
    }
  }
}

设置好前一个结构后，查询如下所示：

 public class DatabaseOpenHelper extends SQLiteOpenHelper {

    private static final String DROP_START_QUERY = "DROP TABLE IF EXISTS ";
    /**
     * database name
     */
    public static final String DATABASE_NAME = "data.db";

    // default statements used for different queries
    public static final String PRIMARY_KEY_STATEMENT = " PRIMARY KEY ";
    public static final String PRIMARY_KEY_AUTOINCREMENT_STATEMENT = " PRIMARY KEY AUTOINCREMENT ";

    private static final String CREATE_TABLE = "CREATE TABLE IF NOT EXISTS ";
    private static final String LEFT_PARENTHESES = "( \n";

    private static final String SPACE_CHARACTER = " ";
    private static final String CONFLICT_REPLACE_TEXT = ") ON CONFLICT IGNORE ";
    public static final String UNIQUE_KEY_STATEMENT = " UNIQUE (";
    // end of default queries

    private static final int DATABASE_VERSION = 19;
    public static final String COMMA_STRING = ",";
    public static final String EMPTY_STRING = "";
    public static final String TAB_STRING = "\n";

    public DatabaseOpenHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        createTables(db);
    }

    private void createTables(SQLiteDatabase db) {
        Collection<String> scripts = createScripts();
        for (String query : scripts) {
            db.execSQL(query);
        }
    }

    private Collection<String> createScripts() {
        Collection<String> scripts = new ArrayList<>();

        for (DatabaseTable table : DatabaseTable.values()) {
            String sqlQuery = CREATE_TABLE + table.getName() + LEFT_PARENTHESES;
            String primaryKeyQuery = getQueryScript(table);
            sqlQuery += primaryKeyQuery;
            sqlQuery += ")\n";
            scripts.add(sqlQuery);
        }
        return scripts;
    }

    private String getQueryScript(DatabaseTable table) {
        String query = "";
        for (int k = 0; k < table.getColumns().length; k++) {
            DatabaseColumn column = table.getColumns()[k];
            query += column.getFieldName() + SPACE_CHARACTER + column.getDataType().getRowType();
            if (column.isPrimaryKey() && column.isAutoIncremented()) {
                query += PRIMARY_KEY_AUTOINCREMENT_STATEMENT;
            } else if (column.isPrimaryKey()) {
                query += PRIMARY_KEY_STATEMENT;
            } else if (column.isUnique()) {
                query += UNIQUE_KEY_STATEMENT + column.getFieldName() + CONFLICT_REPLACE_TEXT;
            }
            query += (k == table.getColumns().length - 1 ? EMPTY_STRING : COMMA_STRING) + TAB_STRING;
        }
        return query;
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        //drop tables
        List<String> dropScripts = createDropScripts();
        for (String query : dropScripts) {
            db.execSQL(query);
        }
    }

    /**
     * creates a list of all the drop table queries and update them
     * to a list so we can delete them in a simple way.
     *
     * @return array list containing the drop table queries.
     */
    private List<String> createDropScripts() {
        List<String> dropScripts = new ArrayList<>();
        DatabaseTable[] tables = DatabaseTable.values();
        for (DatabaseTable table : tables) {
            String query_script = DROP_START_QUERY + table.getName() + " ;";
            dropScripts.add(query_script);
        }
        return dropScripts;
     }
 }

---

不确定我是否理解，但以下是我将要做的。
我会创建一个非常好的结构
首先，我首先会从你的类DayExpensesDB中删除你放在那里的所有东西，成员。相反，我会用脚本创建我的数据库，所有东西都是OOP风格的。 例如，您为包含有关列的内容的列创建了一个类，它是主键，是或不是？它是唯一的还是不唯一的？

编辑
添加了从pastebin中删除的代码

//类，该类描述数据库列。

public class DatabaseColumnImpl implements DatabaseColumn {

    private boolean uniqueField = false;

    private boolean autoIncrement = false;

    private boolean isForeignKey = false;

    private boolean primaryKey = false;

    private String rowName;
    private RowType dataRowType;

     public GenericColumnImpl(boolean primaryKey, boolean autoIncrement, boolean uniqueField, boolean isForeignKey, String fieldName, @NonNull RowType type) {
        this.uniqueField = uniqueField;
        this.primaryKey = primaryKey;
        this.autoIncrement = autoIncrement;
        this.dataRowType = type;
        this.rowName = fieldName;
        this.isForeignKey = isForeignKey;
     }

     public DatabaseColumnImpl(boolean primaryKey, boolean autoIncrement, String fieldName, @NonNull RowType type) {
         this(primaryKey, autoIncrement, false, false, fieldName, type);
     }
    //... setters and getters
}

接下来，我将定义我的数据库契约和要插入的行。例如，您的表要求有4-5列，但尚未知道行（请参见下图）。

//每行的数据库列。

  public enum DatabaseTable{

    DATA(new DatabaseColumnImpl(true, true, DataContract.X._ID, SqliteDataType.Integer),
        new DatabaseColumnImpl(DataContract.X.TIMEDURATION, SqliteDataType.Integer),
        new DatabaseColumnImpl(DataContract.X.DESCRIPTION, SqliteDataType.String),
        new DatabaseColumnImpl(DataContract.X.NAME, SqliteDataType.String));
  //much more data can be added here
   private DatabaseColumnImpl[] genericColumns;

   private DatabaseTable(DatabaseColumnImpl... columns) {
       this.genericColumns = columns;
   }

   public DatabaseColumnImpl[] getColumns() {
       return genericColumns;
   }

   public String getName() {
      return this.name();
   }
}

完成这些之后，我将创建数据库契约类

public class DatabaseContract {
    public static final String CONTENT_STRING = "content://";

    public static final String CONTENT_AUTHORITY = "com.org.data";

    public static final String VND_AUTHORITY = "vnd.org.data";

    public static final Uri BASE_CONTENT_URI = Uri.parse(CONTENT_STRING + CONTENT_AUTHORITY);


    public static final class XData implements BaseColumns {

         public static final String TABLE_NAME = "xdata";

         //content://com.org.data/xdata
         public static final Uri CONTENT_URI = BASE_CONTENT_URI.buildUpon().appendPath(TABLE_NAME).build();

         //vnd.android.cursor.dir/vnd.org.data
         public static final String CONTENT_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE + File.separator + VND_AUTHORITY;

         //vnd.android.cursor.item/vnd.org.data
         public static final String CONTENT_ITEMTYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + File.separator + VND_AUTHORITY;

         public static final String NAME = "name";

         public static final String DESCRIPTION = "description";

         public static final String TIMEDURATION = "time_duration";
         //more data

    public static Uri buildXdataUri(long id) {
        return ContentUris.withAppendedId(CONTENT_URI, id);
    }
  }
}

设置好前一个结构后，查询如下所示：

 public class DatabaseOpenHelper extends SQLiteOpenHelper {

    private static final String DROP_START_QUERY = "DROP TABLE IF EXISTS ";
    /**
     * database name
     */
    public static final String DATABASE_NAME = "data.db";

    // default statements used for different queries
    public static final String PRIMARY_KEY_STATEMENT = " PRIMARY KEY ";
    public static final String PRIMARY_KEY_AUTOINCREMENT_STATEMENT = " PRIMARY KEY AUTOINCREMENT ";

    private static final String CREATE_TABLE = "CREATE TABLE IF NOT EXISTS ";
    private static final String LEFT_PARENTHESES = "( \n";

    private static final String SPACE_CHARACTER = " ";
    private static final String CONFLICT_REPLACE_TEXT = ") ON CONFLICT IGNORE ";
    public static final String UNIQUE_KEY_STATEMENT = " UNIQUE (";
    // end of default queries

    private static final int DATABASE_VERSION = 19;
    public static final String COMMA_STRING = ",";
    public static final String EMPTY_STRING = "";
    public static final String TAB_STRING = "\n";

    public DatabaseOpenHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        createTables(db);
    }

    private void createTables(SQLiteDatabase db) {
        Collection<String> scripts = createScripts();
        for (String query : scripts) {
            db.execSQL(query);
        }
    }

    private Collection<String> createScripts() {
        Collection<String> scripts = new ArrayList<>();

        for (DatabaseTable table : DatabaseTable.values()) {
            String sqlQuery = CREATE_TABLE + table.getName() + LEFT_PARENTHESES;
            String primaryKeyQuery = getQueryScript(table);
            sqlQuery += primaryKeyQuery;
            sqlQuery += ")\n";
            scripts.add(sqlQuery);
        }
        return scripts;
    }

    private String getQueryScript(DatabaseTable table) {
        String query = "";
        for (int k = 0; k < table.getColumns().length; k++) {
            DatabaseColumn column = table.getColumns()[k];
            query += column.getFieldName() + SPACE_CHARACTER + column.getDataType().getRowType();
            if (column.isPrimaryKey() && column.isAutoIncremented()) {
                query += PRIMARY_KEY_AUTOINCREMENT_STATEMENT;
            } else if (column.isPrimaryKey()) {
                query += PRIMARY_KEY_STATEMENT;
            } else if (column.isUnique()) {
                query += UNIQUE_KEY_STATEMENT + column.getFieldName() + CONFLICT_REPLACE_TEXT;
            }
            query += (k == table.getColumns().length - 1 ? EMPTY_STRING : COMMA_STRING) + TAB_STRING;
        }
        return query;
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        //drop tables
        List<String> dropScripts = createDropScripts();
        for (String query : dropScripts) {
            db.execSQL(query);
        }
    }

    /**
     * creates a list of all the drop table queries and update them
     * to a list so we can delete them in a simple way.
     *
     * @return array list containing the drop table queries.
     */
    private List<String> createDropScripts() {
        List<String> dropScripts = new ArrayList<>();
        DatabaseTable[] tables = DatabaseTable.values();
        for (DatabaseTable table : tables) {
            String query_script = DROP_START_QUERY + table.getName() + " ;";
            dropScripts.add(query_script);
        }
        return dropScripts;
     }
 }

---

不确定我是否理解，但以下是我将要做的。
我会创建一个非常好的结构
首先，我首先会从你的类DayExpensesDB中删除你放在那里的所有东西，成员。相反，我会用脚本创建我的数据库，所有东西都是OOP风格的。 例如，您为包含有关列的内容的列创建了一个类，它是主键，是或不是？它是唯一的还是不唯一的？

编辑
添加了从pastebin中删除的代码

//类，该类描述数据库列。

public class DatabaseColumnImpl implements DatabaseColumn {

    private boolean uniqueField = false;

    private boolean autoIncrement = false;

    private boolean isForeignKey = false;

    private boolean primaryKey = false;

    private String rowName;
    private RowType dataRowType;

     public GenericColumnImpl(boolean primaryKey, boolean autoIncrement, boolean uniqueField, boolean isForeignKey, String fieldName, @NonNull RowType type) {
        this.uniqueField = uniqueField;
        this.primaryKey = primaryKey;
        this.autoIncrement = autoIncrement;
        this.dataRowType = type;
        this.rowName = fieldName;
        this.isForeignKey = isForeignKey;
     }

     public DatabaseColumnImpl(boolean primaryKey, boolean autoIncrement, String fieldName, @NonNull RowType type) {
         this(primaryKey, autoIncrement, false, false, fieldName, type);
     }
    //... setters and getters
}

接下来，我将定义我的数据库契约和要插入的行。例如，您的表要求有4-5列，但尚未知道行（请参见下图）。

//每行的数据库列。

  public enum DatabaseTable{

    DATA(new DatabaseColumnImpl(true, true, DataContract.X._ID, SqliteDataType.Integer),
        new DatabaseColumnImpl(DataContract.X.TIMEDURATION, SqliteDataType.Integer),
        new DatabaseColumnImpl(DataContract.X.DESCRIPTION, SqliteDataType.String),
        new DatabaseColumnImpl(DataContract.X.NAME, SqliteDataType.String));
  //much more data can be added here
   private DatabaseColumnImpl[] genericColumns;

   private DatabaseTable(DatabaseColumnImpl... columns) {
       this.genericColumns = columns;
   }

   public DatabaseColumnImpl[] getColumns() {
       return genericColumns;
   }

   public String getName() {
      return this.name();
   }
}

完成这些之后，我将创建数据库契约类

public class DatabaseContract {
    public static final String CONTENT_STRING = "content://";

    public static final String CONTENT_AUTHORITY = "com.org.data";

    public static final String VND_AUTHORITY = "vnd.org.data";

    public static final Uri BASE_CONTENT_URI = Uri.parse(CONTENT_STRING + CONTENT_AUTHORITY);


    public static final class XData implements BaseColumns {

         public static final String TABLE_NAME = "xdata";

         //content://com.org.data/xdata
         public static final Uri CONTENT_URI = BASE_CONTENT_URI.buildUpon().appendPath(TABLE_NAME).build();

         //vnd.android.cursor.dir/vnd.org.data
         public static final String CONTENT_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE + File.separator + VND_AUTHORITY;

         //vnd.android.cursor.item/vnd.org.data
         public static final String CONTENT_ITEMTYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + File.separator + VND_AUTHORITY;

         public static final String NAME = "name";

         public static final String DESCRIPTION = "description";

         public static final String TIMEDURATION = "time_duration";
         //more data

    public static Uri buildXdataUri(long id) {
        return ContentUris.withAppendedId(CONTENT_URI, id);
    }
  }
}

设置好前一个结构后，查询如下所示：

 public class DatabaseOpenHelper extends SQLiteOpenHelper {

    private static final String DROP_START_QUERY = "DROP TABLE IF EXISTS ";
    /**
     * database name
     */
    public static final String DATABASE_NAME = "data.db";

    // default statements used for different queries
    public static final String PRIMARY_KEY_STATEMENT = " PRIMARY KEY ";
    public static final String PRIMARY_KEY_AUTOINCREMENT_STATEMENT = " PRIMARY KEY AUTOINCREMENT ";

    private static final String CREATE_TABLE = "CREATE TABLE IF NOT EXISTS ";
    private static final String LEFT_PARENTHESES = "( \n";

    private static final String SPACE_CHARACTER = " ";
    private static final String CONFLICT_REPLACE_TEXT = ") ON CONFLICT IGNORE ";
    public static final String UNIQUE_KEY_STATEMENT = " UNIQUE (";
    // end of default queries

    private static final int DATABASE_VERSION = 19;
    public static final String COMMA_STRING = ",";
    public static final String EMPTY_STRING = "";
    public static final String TAB_STRING = "\n";

    public DatabaseOpenHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        createTables(db);
    }

    private void createTables(SQLiteDatabase db) {
        Collection<String> scripts = createScripts();
        for (String query : scripts) {
            db.execSQL(query);
        }
    }

    private Collection<String> createScripts() {
        Collection<String> scripts = new ArrayList<>();

        for (DatabaseTable table : DatabaseTable.values()) {
            String sqlQuery = CREATE_TABLE + table.getName() + LEFT_PARENTHESES;
            String primaryKeyQuery = getQueryScript(table);
            sqlQuery += primaryKeyQuery;
            sqlQuery += ")\n";
            scripts.add(sqlQuery);
        }
        return scripts;
    }

    private String getQueryScript(DatabaseTable table) {
        String query = "";
        for (int k = 0; k < table.getColumns().length; k++) {
            DatabaseColumn column = table.getColumns()[k];
            query += column.getFieldName() + SPACE_CHARACTER + column.getDataType().getRowType();
            if (column.isPrimaryKey() && column.isAutoIncremented()) {
                query += PRIMARY_KEY_AUTOINCREMENT_STATEMENT;
            } else if (column.isPrimaryKey()) {
                query += PRIMARY_KEY_STATEMENT;
            } else if (column.isUnique()) {
                query += UNIQUE_KEY_STATEMENT + column.getFieldName() + CONFLICT_REPLACE_TEXT;
            }
            query += (k == table.getColumns().length - 1 ? EMPTY_STRING : COMMA_STRING) + TAB_STRING;
        }
        return query;
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        //drop tables
        List<String> dropScripts = createDropScripts();
        for (String query : dropScripts) {
            db.execSQL(query);
        }
    }

    /**
     * creates a list of all the drop table queries and update them
     * to a list so we can delete them in a simple way.
     *
     * @return array list containing the drop table queries.
     */
    private List<String> createDropScripts() {
        List<String> dropScripts = new ArrayList<>();
        DatabaseTable[] tables = DatabaseTable.values();
        for (DatabaseTable table : tables) {
            String query_script = DROP_START_QUERY + table.getName() + " ;";
            dropScripts.add(query_script);
        }
        return dropScripts;
     }
 }

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不确定我是否理解，但以下是我将要做的。
我会创建一个非常好的结构
首先，我首先会从你的类DayExpensesDB中删除你放在那里的所有东西，成员。相反，我会用脚本创建我的数据库，所有东西都是OOP风格的。 例如，您创建了一个