sqlite查询失败-没有这样的列 [英] sqlite query failing - no such column
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问题描述
我有一个这样创建的数据库...
I have a db that is created like this...
public class DataBaseManager extends SQLiteOpenHelper{
Context mContext;
private static final String TAG = "DataBaseManager";
private static final int dbVersion = 1;// ++ for DB changes
static final String dbName ="LCInstore";
//Table Names
static final String allIcons = "Icons";
static final String allScreens = "Screens";
static final String isLookUp = "LookUp";
//Column Names - LookUp
static final String colIconID = "IconID";
static final String colScreenID = "ScreenID";
static final String colRank = "Rank"; // order
//Column Names shared by tables: Screens and Icons
static final String colID = "ID";
static final String colType = "Type";
static final String colName = "Name";
//Column Names - Icons
static final String colImage = "Image";
static final String colLabel = "Label";
static final String colIntent = "Intent";
static final String colIParams = "Params";
public DataBaseManager(Context context) {
super(context, dbName, null, dbVersion);
mContext = context;
Log.v(TAG, "Initaited");
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
Log.v(TAG, "on create called");
// Create Icon Table if does not exist
db.execSQL("CREATE TABLE "+ allIcons +"" +
"("+colID + " INTEGER PRIMARY KEY AUTOINCREMENT, "+
colName + " TEXT," +
colImage + " BLOB," +
colLabel + " TEXT," +
colIntent + " TEXT," +
colType + " TEXT)");
// Create Screens Table if does not exist
db.execSQL("CREATE TABLE IF NOT EXISTS " + allScreens +"" +
"("+colID + " INTEGER PRIMARY KEY AUTOINCREMENT, "+
colName + " TEXT," +
colType + " TEXT)");
//Create LookUp Table if does not exist
db.execSQL("CREATE TABLE IF NOT EXISTS " + isLookUp +"" +
"("+colIconID + " INTEGER, "+
colScreenID + " INTEGER," +
colRank + " INTEGER)");
InsertInitData(db);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
Log.v(TAG, "on upgrade called");
//db.execSQL("DROP TABLE IF EXISTS "+allIcons);
}
private void InsertInitData(SQLiteDatabase db) {
//screens
ContentValues cv2=new ContentValues();
cv2.put(colName, "DR_Home");
cv2.put(colType, "dr_home");
db.insert(allScreens, colID, cv2);
cv2.put(colName, "DR_Sub");
cv2.put(colType, "dr_sub");
db.insert(allScreens, colID, cv2);
//all Icons
ContentValues cv=new ContentValues();
cv.put(colName, "Icon1");
cv.put(colImage, getBlobFromRes(R.drawable.dr_tablet_icon));
cv.put(colLabel, "MY ICON 1");
cv.put(colIntent, "someIntent");
cv.put(colType, "generic");
db.insert(allIcons, colID, cv);
cv.put(colName, "Icon2");
cv.put(colImage, getBlobFromRes(R.drawable.dr_tablet_icon));
cv.put(colLabel, "MY ICON 2");
cv.put(colIntent, "someIntent");
cv.put(colType, "generic");
db.insert(allIcons, colID, cv);
cv.put(colName, "Icon3");
cv.put(colImage, getBlobFromRes(R.drawable.dr_tablet_icon));
cv.put(colLabel, "MY ICON 3");
cv.put(colIntent, "someIntent");
cv.put(colType, "generic");
db.insert(allIcons, colID, cv);
cv.put(colName, "Icon4");
cv.put(colImage, getBlobFromRes(R.drawable.dr_tablet_icon));
cv.put(colLabel, "MY ICON 4");
cv.put(colIntent, "someIntent");
cv.put(colType, "generic");
db.insert(allIcons, colID, cv);
cv.put(colName, "Icon5");
cv.put(colImage, getBlobFromRes(R.drawable.dr_tablet_icon));
cv.put(colLabel, "MY ICON 5");
cv.put(colIntent, "someIntent");
cv.put(colType, "generic");
db.insert(allIcons, colID, cv);
cv.put(colName, "Icon6");
cv.put(colImage, getBlobFromRes(R.drawable.dr_tablet_icon));
cv.put(colLabel, "MY ICON 6");
cv.put(colIntent, "someIntent");
cv.put(colType, "generic");
db.insert(allIcons, colID, cv);
cv.put(colName, "Icon7");
cv.put(colImage, getBlobFromRes(R.drawable.dr_tablet_icon));
cv.put(colLabel, "MY ICON 7");
cv.put(colIntent, "someIntent");
cv.put(colType, "generic");
db.insert(allIcons, colID, cv);
// icon screen lookups
ContentValues cv3=new ContentValues();
cv3.put(colIconID, 1);
cv3.put(colScreenID, 2);
cv3.put(colRank, 1);
db.insert(isLookUp, colID, cv3);
cv3.put(colIconID, 2);
cv3.put(colScreenID, 2);
cv3.put(colRank, 2);
db.insert(isLookUp, colID, cv3);
cv3.put(colIconID, 3);
cv3.put(colScreenID, 2);
cv3.put(colRank, 3);
db.insert(isLookUp, colID, cv3);
cv3.put(colIconID, 4);
cv3.put(colScreenID, 2);
cv3.put(colRank, 4);
db.insert(isLookUp, colID, cv3);
cv3.put(colIconID, 5);
cv3.put(colScreenID, 2);
cv3.put(colRank, 5);
db.insert(isLookUp, colID, cv3);
cv3.put(colIconID, 6);
cv3.put(colScreenID, 2);
cv3.put(colRank, 6);
db.insert(isLookUp, colID, cv3);
cv3.put(colIconID, 7);
cv3.put(colScreenID, 2);
cv3.put(colRank, 7);
db.insert(isLookUp, colID, cv3);
}
您会注意到，一个表"allScreens"或"Screens"具有一行，我在名称"列中放置了"DR_Home"
you'll notice that one table, 'allScreens' or "Screens" has one row that in the Name column i am putting "DR_Home"
稍后，我进行查询以使用该方法找出该行的ID列的值，并将 DR_Home 传递给它:
i do a query later to find out the value of the ID column of that row using this method and passing DR_Home to it:
public int getScreenID(String name){
SQLiteDatabase db=this.getReadableDatabase();
int sID;
String selectQuery = "SELECT "+colID+ " FROM " + allScreens + " WHERE " + colName + "=" +name;
Cursor c = db.rawQuery(selectQuery, null);
sID = c.getInt(0);
c.close();
return sID;
}
应返回ID列的值，但出现错误:
should return the value of the ID column but i am getting an error:
03-22 06:34:35.830: E/AndroidRuntime(29864): Caused by: android.database.sqlite.SQLiteException: no such column: DR_Home: , while compiling: select * from Screens WHERE Name=DR_Home
没有这样的专栏吗?我没有要求一个名为DR_Home的列，而是在Name列= DR_home的行中要求ID列的值.至少那是我的想法..我在某个地方弄乱了语法..请帮助
No such Column? im not asking for a column called DR_Home i am asking for the value of the ID column in the row where the Name column = DR_home.. at least thats what i thought.. i have messed up the syntax somewhere.. please help
推荐答案
您的查询错误，因为 WHERE column = string 无效.
Your query is wrong, as WHERE column = string will not work.
String selectQuery = "SELECT "+colID+ " FROM " + allScreens + " WHERE " + colName + "=?";
Cursor c = db.rawQuery(selectQuery, new String[] {name});
使用?，它将被第二个 rawQuery()参数替换.强烈推荐.
Use ? which will be replaced by the second rawQuery() parameter. Strongly recommended.
不推荐: WHERE column ="string"
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