SQLite的查询停止递增10 [英] SQLite Query Stops Incrementing at 10

问题描述

我在Android SQLite数据库插入查询。我需要保持这种自动递增为每个新记录的键ID字段。因此，作为安装到我的INSERT命令的一部分，我觉得在这方面的最大值，然后加一。事实证明，我的code停在10递增一切是罚款的第9插入，但我没有得到比10更高的我在做什么错了？谢谢！

在这里，code：

 公共布尔createSubcategory（字符串subcategoryName）{    接下来INT;
    ContentValues​​ newValues​​ =新ContentValues​​（）;
    SQLiteDatabase分贝= myDBOpenHelper.getWritableDatabase（）;    / *获得在子类表中的最大值 - 这是递增数
     *和指定为subcategory_id为我们的新的子类别记录* /
    光标= db.query（SUBCATEGORIES_TABLE，新的String [] {MAX（+ SUBCATEGORY_ID_COLUMN +）作为COL}，NULL，NULL，NULL，NULL，NULL）;    / *插入一行到小类表* /
    如果（cursor.getCount（）大于0）{
        cursor.moveToFirst（）;
        接下来= cursor.getInt（cursor.getColumnIndex（COL））+ 1;
    }其他{下一= 1;}    newValues​​.put（SUBCATEGORY_ID_COLUMN，旁边）;
    newValues​​.put（SUBCATEGORY_COLUMN，subcategoryName）;    db.insert（SUBCATEGORIES_TABLE，空，newValues​​）;
    cursor.close（）;    通信System.err.println（新子记录创建：ID：+ +旁边名称：+ subcategoryName +类别ID：+的categoryID）;    返回true;
}
 

下面是我如何把这个从MainActivity：

 私人无效createSubcategories（MYDB DB）{
    db.createSubcategory（爵士）;
    db.createSubcategory（乐团）;
    db.createSubcategory（岩石）;
    db.createSubcategory（品酒）;
    db.createSubcategory（讲座）;
    db.createSubcategory（新书签售）;
    db.createSubcategory（篮球）;
    db.createSubcategory（棒球）;
    db.createSubcategory（足球）;
    db.createSubcategory（曲棍球）;
    db.createSubcategory（其他）;
    db.createSubcategory（向上计数器测试）;
}
 

这是我得到的输出。见subcategory_id如何停止在10？

  

新的子类别记录创建：ID：1名称：爵士

  
  

新的子类别记录创建：ID：2名：乐团

  
  

新的子类别记录创建：ID：3名称：Rock

  
  

新的子类别记录创建：ID：4名：品酒

  
  

新的子类别记录创建：ID：5名：讲座

  
  

新的子类别记录创建：ID：6名称：新书签售

  
  

新的子类别记录创建：ID：7名：篮球

  
  

新的子类别记录创建：ID：8名：棒球

  
  

新的子类别记录创建：ID：9产品名称：足球

  
  

新的子类别记录创建：ID：10姓名：曲棍球

  
  

新的子类别记录创建：ID：10姓名：其他

  
  

新的子类别记录创建：ID：10姓名：向上计数器测试

解决方案

这是非常有可能的是搜索使用字典序做，自9，在ASCII-betical订单10后到来的时候，您的查询始终返回9和明年将永远是10。

是您的ID字符串？

I have an insert query in an Android SQLite database. I need to keep a key id field that autoincrements for each new record. So as part of the setup to my insert command, I find the max value in this field and then increment it. It turns out that my code stops incrementing at 10. Everything is fine for the first 9 inserts, but I don't get higher than 10. What am I doing wrong??? Thanks!

Here the code:

public boolean createSubcategory(String subcategoryName) {

    int next;
    ContentValues newValues = new ContentValues();
    SQLiteDatabase db = myDBOpenHelper.getWritableDatabase();

    /* get the maximum value in the sub category table - this is the number to increment
     * and assign as the subcategory_id for our new subcategory record */
    cursor = db.query(SUBCATEGORIES_TABLE, new String [] {"MAX("+SUBCATEGORY_ID_COLUMN+") AS COL"}, null, null, null, null, null);

    /* Insert a row into the Subcategories table */
    if ( cursor.getCount() > 0 ) {
        cursor.moveToFirst();
        next = cursor.getInt(cursor.getColumnIndex("COL")) + 1;
    } else {next = 1;}

    newValues.put(SUBCATEGORY_ID_COLUMN, next);
    newValues.put(SUBCATEGORY_COLUMN, subcategoryName);

    db.insert(SUBCATEGORIES_TABLE, null, newValues);
    cursor.close();     

    System.err.println("New subcategory record created: ID: " + next + " Name: " + subcategoryName + "  Category ID: " + categoryID);

    return true;
}   

Here is how I call this from MainActivity:

private void createSubcategories(myDB db) {
    db.createSubcategory("Jazz");
    db.createSubcategory("Orchestra");
    db.createSubcategory("Rock");
    db.createSubcategory("Wine Tasting");
    db.createSubcategory("Lectures");
    db.createSubcategory("Book Signings");
    db.createSubcategory("Basketball");
    db.createSubcategory("Baseball");
    db.createSubcategory("Football");
    db.createSubcategory("Hockey");
    db.createSubcategory("Other");
    db.createSubcategory("Incrementer Test");
}

And this is the output that I get. See how the subcategory_id stops at 10?

New subcategory record created: ID: 1 Name: Jazz

New subcategory record created: ID: 2 Name: Orchestra

New subcategory record created: ID: 3 Name: Rock

New subcategory record created: ID: 4 Name: Wine Tasting

New subcategory record created: ID: 5 Name: Lectures

New subcategory record created: ID: 6 Name: Book Signings

New subcategory record created: ID: 7 Name: Basketball

New subcategory record created: ID: 8 Name: Baseball

New subcategory record created: ID: 9 Name: Football

New subcategory record created: ID: 10 Name: Hockey

New subcategory record created: ID: 10 Name: Other

New subcategory record created: ID: 10 Name: Incrementer test

解决方案

It's very likely that the search is made using lexicographical order, and since "9" comes after "10" in "ASCII-betical" order, your query always return 9 and next will always be 10.

Is your ID a string?

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