插入的外键到表 [英] Inserting a foreign key into a table

问题描述

如何插入的外键到表？我有两个表（信息和WorkDetails），其中WorkDetails具有参考信息的外键。这是实施正确的方法是什么？

MyDatabaseHelper.java

 公共无效的onCreate（SQLiteDatabase DB）
    {
       db.execSQL（CREATE TABLE+ TABLE_INFO +（ID INTEGER PRIMARY KEY，Name文本，天气文本，日期DATETIME，状态文本））;
       db.execSQL（CREATE TABLE+ TABLE_WORKDETAILS +（ID INTEGER PRIMARY KEY，项目文本，WorkDescription TEXT，每文本，TimeIn DATETIME，超时DATETIME，TotalHours DATETIME，TableInfo_id INTEGER，外键（TableInfo_id）参考文献TABLE_INFO（ID）） ;
    }
 

WorkDetailsAPI.java

 公共类WorkDetailsAPI {
    私人SQLiteDatabase数据库;
    私人MyDatabaseHelper dbHelper;
    公众的String [] allColumns={MyDatabaseHelper.ID2,MyDatabaseHelper.Project,MyDatabaseHelper.WorkDescription,MyDatabaseHelper.Per,MyDatabaseHelper.TimeIn,MyDatabaseHelper.TimeOut,MyDatabaseHelper.TotalHours,MyDatabaseHelper.TableInfo_id};    公共WorkDetailsAPI（上下文的背景下）
                   ....
    众长insertWorkDetails（字符串项目，字符串workDescription，每串，串timeIn，超时字符串，字符串totalHours）
    {
        数据库= dbHelper.getWritableDatabase（）;
        ContentValues​​值=新ContentValues​​（）;
        values​​.put（MyDatabaseHelper.Project，项目）;
        values​​.put（MyDatabaseHelper.WorkDescription，workDescription）;
        values​​.put（MyDatabaseHelper.Per，份）;
        values​​.put（MyDatabaseHelper.TimeIn，timeIn）;
        values​​.put（MyDatabaseHelper.TimeOut，超时）;
        values​​.put（MyDatabaseHelper.TotalHours，totalHours）;
        database.insert（MyDatabaseHelper.TABLE_WORKDETAILS，空，价值）;
        database.close（）;
        返回0;    }}
 

WorkDetails.java

 公共无效的add（）{
    button.setOnClickListener
        .....
            TI.insertTableInfo（姓名，天气，日期，状态）;
            WD.insertWorkDetails（A，B，C，D，E，F）; //我需要包括foreign key？
}
 

解决方案

是你做了正确的方式。

How to insert foreign key into a table? I have two table (Info and WorkDetails) where WorkDetails has a foreign key which refer to Info. Is this the correct way to implement?

MyDatabaseHelper.java

 public void onCreate(SQLiteDatabase db)
    {
       db.execSQL("create table "+TABLE_INFO+"(ID INTEGER PRIMARY KEY ,Name TEXT,Weather TEXT, Date DATETIME, Status Text)");
       db.execSQL("create table"+TABLE_WORKDETAILS+"(ID INTEGER PRIMARY KEY , Project TEXT, WorkDescription TEXT, Per Text, TimeIn DATETIME, TimeOut DATETIME,TotalHours DATETIME, TableInfo_id INTEGER, FOREIGN KEY(TableInfo_id)REFERENCES TABLE_INFO(ID)");
    }

WorkDetailsAPI.java

public class WorkDetailsAPI {
    private SQLiteDatabase database;
    private MyDatabaseHelper dbHelper;
    public String[] allColumns={MyDatabaseHelper.ID2,MyDatabaseHelper.Project,MyDatabaseHelper.WorkDescription,MyDatabaseHelper.Per,MyDatabaseHelper.TimeIn,MyDatabaseHelper.TimeOut,MyDatabaseHelper.TotalHours,MyDatabaseHelper.TableInfo_id};

    public WorkDetailsAPI(Context context)
                   ....
    public long insertWorkDetails(String project, String workDescription, String per,String timeIn,String timeOut,String totalHours)
    {
        database=dbHelper.getWritableDatabase();
        ContentValues values=new ContentValues();
        values.put(MyDatabaseHelper.Project,project);
        values.put(MyDatabaseHelper.WorkDescription,workDescription);
        values.put(MyDatabaseHelper.Per,per);
        values.put(MyDatabaseHelper.TimeIn,timeIn);
        values.put(MyDatabaseHelper.TimeOut,timeOut);
        values.put(MyDatabaseHelper.TotalHours,totalHours);
        database.insert(MyDatabaseHelper.TABLE_WORKDETAILS,null,values);
        database.close();
        return 0 ;

    }

}

WorkDetails.java

public void add() {
    button.setOnClickListener
        .....
            TI.insertTableInfo(name,weather,date,status);
            WD.insertWorkDetails(a,b,c,d,e,f); // Do I need to include the foreign key?
}

解决方案

Yes you're doing it the right way

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