Java &引用；没有这样的专栏“；在SQLite上运行更新时

我正在尝试更新数据库中的一行。以下是我试图用来更新的代码：

public void addFBComments(int id){ 
    SQLiteDatabase db = this.getWritableDatabase(); 
    String query = "UPDATE " + TABLE_FB_FEED + " SET " + COL_FB_COMMENTS+"="+"HELLO" + " WHERE " + COL_FB_ID+"="+id;

    db.execSQL(query);
}

当我运行该命令时，它会抛出以下错误：

08-18 15:42:10.145: E/AndroidRuntime(10493): FATAL EXCEPTION: Thread-922
08-18 15:42:10.145: E/AndroidRuntime(10493): android.database.sqlite.SQLiteException: no such column: HELLO (code 1): , while compiling: UPDATE fb_feed SET fb_comments= HELLO  WHERE _id=3

以下是表格\u FB\u提要：

private static final String TABLE_FB_FEED_CREATE = "create table " + TABLE_FB_FEED + 
" ("
        + COL_FB_ID + " integer primary key autoincrement not null," 
        + COL_FB_MESSAGE + " text," 
        + COL_FB_CAPTION + " text,"
        + COL_FB_POSTER_ID + " text,"
        + COL_FB_POST_ID + " text,"
        + COL_FB_LIKES + " text,"
        + COL_FB_POSTER_NAME + " text,"
        + COL_FB_COMMENTS + " text," // this is the column i want to update
        + COL_FB_LIKES_NUM + " text,"
        + COL_FB_TIMESTAMP + " text,"
        + COL_FB_PROFILE_PICTURE_URI + " text,"
        + COL_FB_PICTURE_URI + " text," 
        + COL_FB_NAME + " text," 
        + COL_FB_PREVIOUS_PAGE_URI + " text,"
        + COL_FB_NEXT_PAGE_URI + " text," 
        + COL_FB_POST_TYPE + " text," 
        + COL_FB_LINK_NAME + " text," 
        + COL_FB_COMMENTS_NUM + " text," 
        + COL_FB_STORY + " text," 
        + COL_FB_DESCRIPTION + " text,"
        + COL_FB_COMMENTS_BEFORE + " text,"
        + COL_FB_COMMENTS_AFTER + " text,"
        + COL_FB_LIKES_PROFILE_PIC + " text,"
        + COL_FB_COMMENTS_PROFILE_PIC + " text);";

---

为什么它要抛出这个问题？我认为我做的一切都是正确的。

您需要转义字符串文字

String query = "UPDATE " + TABLE_FB_FEED + " SET " + COL_FB_COMMENTS
    +"="+"HELLO" + " WHERE " + COL_FB_ID+"="+id

可能是

String query = "UPDATE " + TABLE_FB_FEED + " SET " + COL_FB_COMMENTS
    +"="+"'HELLO'" + " WHERE " + COL_FB_ID+"="+id

或者，您可以使用bind参数。

类似于

String query = "UPDATE " + TABLE_FB_FEED + " SET " + COL_FB_COMMENTS+"="+"'HELLO'" + " WHERE " + COL_FB_ID+"="+id;

---

如果要在SQL中工作，则必须引用字符串值：

String query = "..." + COL_FB_COMMENTS+"= 'HELLO' WHERE ...";

无论如何，通过使用以下参数可以避免此类格式问题（当字符串本身包含引号时会变得更糟）：

String query = "... SET " + COL_FB_COMMENTS+"= ?  WHERE " + COL_FB_ID+"="+id;
db.execSQL(query, new Object[] { "HELLO" });

---

在代码中，您需要添加单引号：

String query = "UPDATE " + TABLE_FB_FEED + " SET " + COL_FB_COMMENTS
    +"="+"'HELLO'" + " WHERE " + COL_FB_ID+"="+id

或

这是另一个例子

"UPDATE DB_TABLE SET YOUR_COLUMN='newValue' WHERE id=myidValue");

"UPDATE DB_TABLE SET YOUR_COLUMN='newValue' WHERE id=myidValue");