Question

我有5个访问权限的表，分别是IDTable，ArtistTable，BandTable，AlbumTable和SongTable。

我应按艺术家ID搜索，插入，删除和更新。首先，我尝试将ID组合在一起，例如将ID相互依赖;

-------------------- BandTable ----------------------
BandID (PK)     BandName
   1            Guns and Roses
   2            Mumford and Sons

------------------- ArtistTable ----------------------
ArtistID (PK)     BandID    ArtistName        BirthDate    City     Country
   1                 2      Marcus Mumford    31.01.1987   London   UK
   2                 2      Winston Marshall  
   3                 2      Ben Lovett   
   4                 2      Ted Dwane   

-------------------- AlbumTable ---------------------
AlbumID (PK)   ArtistID     AlbumName       Year    Genre       AlbumImage
   1               1        Sigh No More    2009    Folk Rock
   2               1        Babel

-------------------- SongTable ----------------------
SongID (PK)    AlbumID     SongName             Duration   Lyricist
   1              1        Little Lion Man        4.06     Mumford and Sons
   2              1        Winter Winds
   3              2        I Will Wait
   4              2        Lover of the Light

然而，每个乐队都有艺术家，但并非每个艺术家都有乐队，所以我不能在这里做出加入声明。

然后我尝试将IDTable中的所有ID组合在一起，如下所示;

--------------------- IDTable ------------------------
ID (PK)      ArtistID        BandID      AlbumID     SongID
1                1              2            1           1
2                1              2            1           2
3                1              2            2           3
4                1              2            2           4
5                2              2            1           1
6                2              2            1           2
7                2              2            2           3
8                2              2            2           4

------------------- ArtistTable ----------------------
ArtistID (PK)   ArtistName        BirthDate    City     Country
   1            Marcus Mumford    31.01.1987   London   UK
   2            Winston Marshall  
   3            Ben Lovett   
   4            Ted Dwane   

-------------------- BandTable ----------------------
BandID (PK)    BandName
   1           Guns and Roses
   2           Mumford and Sons

-------------------- AlbumTable ---------------------
AlbumID (PK)   AlbumName       Year    Genre       AlbumImage
   1           Sigh No More    2009    Folk Rock
   2           Babel

-------------------- SongTable ----------------------
SongID (PK)    SongName             Duration   Lyricist
   1           Little Lion Man        4.06     Mumford and Sons
   2           Winter Winds
   3           I Will Wait
   4           Lover of the Light

（PK）表示主键。

代码是：

String query = "SELECT "
              + " ArtistTable.ArtistName"
              + " ArtistTable.BirthDate"
              + " ArtistTable.City"
              + " ArtistTable.Country"
              + " BandTable.BandName,"
              + " AlbumTable.AlbumName"
              + " AlbumTable.Year"
              + " AlbumTable.Genre"
              + " SongTable.SongName"
              + " SongTable.Duration"
              + " SongTable.Lyricist"

              + "FROM (((IDTable " 

              + "INNER JOIN ArtistTable ON IDTable.ArtistID = ArtistTable.ArtistID) "
              + "INNER JOIN BandTable ON IDTable.BandID = BandTable.BandID) "
              + "INNER JOIN AlbumTable ON IDTable.AlbumID = AlbumTable.AlbumID) "
              + "INNER JOIN SongTable ON IDTable.SongID = SongTable.SongID "

              + "WHERE IDTable.ID=" +ID+";";

但它没有用。我不知道是否给出了主键错误或代码错误。

谢谢。

Answer 1

试试这个：

String query = "SELECT "
              + " ArtistTable.ArtistName,"
              + " ArtistTable.BirthDate,"
              + " ArtistTable.City,"
              + " ArtistTable.Country,"
              + " BandTable.BandName,"
              + " AlbumTable.AlbumName,"
              + " AlbumTable.Year,"
              + " AlbumTable.Genre,"
              + " SongTable.SongName,"
              + " SongTable.Duration,"
              + " SongTable.Lyricist"

              + "FROM IDTable " 

              + "INNER JOIN ArtistTable ON IDTable.ArtistID = ArtistTable.ArtistID "
              + "INNER JOIN BandTable ON IDTable.BandID = BandTable.BandID "
              + "INNER JOIN AlbumTable ON IDTable.AlbumID = AlbumTable.AlbumID "
              + "INNER JOIN SongTable ON IDTable.SongID = SongTable.SongID "

              + "WHERE IDTable.ID=" +ID+";";

访问中的SQL查询

1 个答案: