如何创建复合主键android

Question

我正在制作一个android数据存储应用程序.在这个我的问题是我想在sqlite表android中创建复合主键.我想要两个列名的复合键.句法:

public static final String PEN_TABLE_QUERY= " CREATE TABLE if not exists " + PEN_TABLE + "( "+ PEN_ID + " INTEGER  , " + MAIN_CATEGORY + " TEXT , " + SUB_CATEGORY + " TEXT , " + PEN_TYPE + " TEXT , " +  DESC + " TEXT , " + DATE + " TEXT PRIMARY KEY " +")";    

我想要id和日期的主键请帮助我

Answer 1

要创建复合主键,请将表约束添加为PRIMARY KEY(column1, column2).您当前的语句使DATE列成为主键.正确的语法是:

"CREATE TABLE table_name ([columns definitions...], PRIMARY KEY (column1_name, column2_name));"

Doc:http://www.sqlite.org/lang_createtable.html