Question

我有一个带有int列的版本1数据库。在版本2中，我想让我的列可以为空，为了实现这一点，我已经将我的列数据类型从我的java实体类中的int更改为Integer。

经过一些研究后，我意识到不可能只更改列的数据类型。

这是我在迁移方法中所做的事情：

我的原始实体名称是TaskEntity，我正在创建一个新的临时表，复制数据然后删除原始表，然后将临时表重命名为原始表。

        database.execSQL(
                "BEGIN TRANSACTION;" +

                "CREATE TABLE TaskEntityNew('id' INTEGER PRIMARY KEY AUTOINCREMENT," +
                        "'text' TEXT," +
                        "'caseid' INTEGER NULL," +
                        "'status' INTEGER NOT NULL DEFAULT 0," +
                        "'datetime' DATETIME," +
                        ",'updateDt' DATETIME," +
                        " FOREIGN KEY (caseid) REFERENCES CaseEntity(id));" +

                "INSERT INTO TaskEntityNew(text,caseid,status,datetime,updateDt) SELECT text,caseid,status,datetime,update FROM TaskEntity;"+

                "DROP TABLE TaskEntity;" +

                "ALTER TABLE 'TaskEntityNew' RENAME TO 'TaskEntity';" +

                "COMMIT;"
        );

但我收到此错误

 Caused by: java.lang.IllegalStateException: Migration didn't properly handle TaskEntity(EntityCollection.TaskEntity).
                                                                                 Expected:
                                                                                TableInfo{name='TaskEntity', columns={text=Column{name='text', type='TEXT', notNull=false, primaryKeyPosition=0}, updateDt=Column{name='updateDt', type='INTEGER', notNull=false, primaryKeyPosition=0}, datetime=Column{name='datetime', type='INTEGER', notNull=false, primaryKeyPosition=0}, status=Column{name='status', type='INTEGER', notNull=true, primaryKeyPosition=0}, caseid=Column{name='caseid', type='INTEGER', notNull=false, primaryKeyPosition=0}, id=Column{name='id', type='INTEGER', notNull=true, primaryKeyPosition=1}}, foreignKeys=[ForeignKey{referenceTable='CaseEntity', onDelete='CASCADE', onUpdate='NO ACTION', columnNames=[caseid], referenceColumnNames=[id]}], indices=[Index{name='index_TaskEntity_caseid', unique=false, columns=[caseid]}]}
                                                                                 Found:
                                                                                TableInfo{name='TaskEntity', columns={text=Column{name='text', type='TEXT', notNull=false, primaryKeyPosition=0}, updateDt=Column{name='updateDt', type='INTEGER', notNull=false, primaryKeyPosition=0}, datetime=Column{name='datetime', type='INTEGER', notNull=false, primaryKeyPosition=0}, status=Column{name='status', type='INTEGER', notNull=true, primaryKeyPosition=0}, caseid=Column{name='caseid', type='INTEGER', notNull=true, primaryKeyPosition=0}, id=Column{name='id', type='INTEGER', notNull=true, primaryKeyPosition=1}}, foreignKeys=[ForeignKey{referenceTable='CaseEntity', onDelete='CASCADE', onUpdate='NO ACTION', columnNames=[caseid], referenceColumnNames=[id]}], indices=[Index{name='index_TaskEntity_caseid', unique=false, columns=[caseid]}]}

我能想到的一个问题是我的SQL块没有执行，我的旧表数据试图与旧的java实体类匹配。任何帮助将不胜感激！

Answer 1

根据文档，execSQL仅执行一条SQL语句：

要执行的SQL语句。不支持以分号分隔的多个语句。

因此您需要将代码重写为多个调用，例如：

database.execSQL("BEGIN TRANSACTION;");

database.execSQL("CREATE TABLE TaskEntityNew('id' INTEGER PRIMARY KEY AUTOINCREMENT," +
        "'text' TEXT," +
        "'caseid' INTEGER NULL," +
        "'status' INTEGER NOT NULL DEFAULT 0," +
        "'datetime' DATETIME," +
        ",'updateDt' DATETIME," +
        " FOREIGN KEY (caseid) REFERENCES CaseEntity(id));");

database.execSQL("INSERT INTO TaskEntityNew(text,caseid,status,datetime,updateDt) SELECT text,caseid,status,datetime,update FROM TaskEntity;");

database.execSQL("DROP TABLE TaskEntity;");

database.execSQL("ALTER TABLE 'TaskEntityNew' RENAME TO 'TaskEntity';");

database.execSQL("COMMIT;");

按原样，SQLite正在执行“ BEGIN TRANSACTION;”。然后忽略其余的SQL语句。

会议室迁移 - 将INTEGER列类型更改为可为空（SQLLITE）

1 个答案: