Hello I am using a sqlite database in my android application, and I have question:
I am trying to get the last value text(thats the collumn) from the last row from the table TABLE_XYZ... but it does not work.. i am using the following code...what am I doing wrong?
another question is, how can I return two values instead of only one, when I want to get several values from the last row like column text and message?
private static final String KEY_MESSAGE = "message";
private static final String KEY_TEXT = "text";
...
String selectQuery= "SELECT * FROM " + TABLE_XYZ+" ORDER BY column DESC LIMIT 1";
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
cursor.close();
return cursor.getString( cursor.getColumnIndex(KEY_TEXT) );
EDIT:
i hade some errors in my Query,, i fixed it, but still have errors:
String selectQuery= "SELECT * FROM " + TABLE_XYZ + " ORDER BY " + KEY_TEXT+ " DESC LIMIT 1";
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
String str = cursor.getString( cursor.getColumnIndex(KEY_TEXT );
cursor.close();
return str;
while debugging I can see that cursor does have the right values inside... but when i try to get the column value with this command "cursor.getString( cursor.getColumnIndex(KEY_TEXT );"... it does not work...
you are closing cursor before getting it's value
try this :
String selectQuery= "SELECT * FROM " + TABLE_XYZ+" ORDER BY column DESC LIMIT 1";
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
String str = "";
if(cursor.moveToFirst())
str = cursor.getString( cursor.getColumnIndex(KEY_TEXT) );
cursor.close();
return str;
From the android documentation: http://developer.android.com/reference/android/database/Cursor.html
abstract void close()
Closes the Cursor, releasing all of its resources and making it completely invalid.
You are closing the cursor before returningthe string.
Like #whatever5599451 said you should not close the cursor before you get value. Also try a query like this:
String selectQuery = "SELECT column FROM " + TABLE_XYZ +
" ORDER BY column DESC LIMIT 1";
You can specify the columns also specify to return only 1 row.
This will bring back only the column you are ordering by you can also specify more columns example:
String selectQuery = "SELECT column, column2, column3 FROM " + TABLE_XYZ +
" ORDER BY column DESC LIMIT 1";
* means select all columns
to get the last column, use the name of the column instead of " * " (* means all, all the fields)
#Steve: do this:
String selectQuery= "SELECT " + KEY_TEXT + " FROM " + TABLE_XYZ + " ORDER BY " + KEY_TEXT+ " DESC LIMIT 1";
then you get just one String with the last record containing just the right column
Related
public void DBSearchCategory(String tableName) {
// 1st way
String inClause = s1.ListViewCategory.toString();
inClause = inClause.replace("[", "(");
inClause = inClause.replace("]", ")");
// Cursor cursor = database.rawQuery("SELECT CATEGORY FROM " + tableName
// + " WHERE CATEGORY NOT IN " + inClause
// + " ORDER BY RANDOM() LIMIT 1 ", null);
// 2nd way
try {
StringBuilder sb = new StringBuilder("");
for (String param : s1.ListViewCategory) {
sb.append(",").append('"').append(param).append('"');
}
params = sb.toString().substring(1);
Log.v("Tag", "params value is " + params);
} catch (StringIndexOutOfBoundsException e) {
}
Cursor cursor = database.rawQuery("SELECT CATEGORY FROM " + tableName
+ " WHERE CATEGORY NOT IN (?) "
+ " ORDER BY RANDOM() LIMIT 1 ", new String[]{params});
while (cursor.moveToNext()) {
category = cursor.getString(cursor.getColumnIndex("CATEGORY"));
s1.keyCategory = category;
}
cursor.close();
}
s1.ListViewCategory is a String type ArrayList in Singleton class s1, and it has values of categories: "game","country","city","subway","actor","pet" // In Database there are total 33 categories, and I want to exclude these 6 categories that are in s1.ListViewCategory
In rawQuery, I want to exclude categories that are in s1.ListViewCategory, so I tried 2 ways of cursor refering to these 2 stackoverflow questions:
Android - sqlite in clause using string values from array?
///Android - sqlite in clause using values from array
I used WHERE and NOT IN statement to exclude these 6 categories
When I tried 2nd way cursor, I got no error. However, the Sql query did not work. It had to exclude categories that are in String[params], but it did not work. So I used log to see what param is and I got this
2020-01-09 09:16:47.233 8978-8978/com.kj.word V/Tag: params value is
"game","country","city","subway","actor","pet"
When I tried 1st Cursor Category, I got error logcat:
Error Code : 1 (SQLITE_ERROR)
Caused By : SQL(query) error or missing database.
(no such column: game (code 1): , while compiling: SELECT CATEGORY FROM KeyWordDB WHERE CATEGORY
NOT IN (game, country, city, subway, actor, pet) ORDER BY RANDOM() LIMIT 1)
#################################################################
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:1008)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:573)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:59)
at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
at android.database.sqlite.SQLite
I confirmed that there is a database, so I guess it is probably sql query problem ...
So my question is How can I fix 1st or 2nd cursor to exclude categories that are in s1.ListViewCateogry?
I've searched real hard, but I wasn't able to find answer... Ill be real grateful, if someone answers this question
Change the double quotes with single quotes inside the loop that constructs the comma delimited list:
for (String param : s1.ListViewCategory) {
sb.append(",").append("'").append(param).append("'");
}
params = sb.toString().substring(1);
This code constructs a list like:
'game', 'country', 'city', 'subway', 'actor', 'pet'
If you use it as a parameter in the rawQuery() method then this list will be treated as a string literal and not a list of values.
So do this instead:
String sql = "SELECT CATEGORY FROM " + tableName
+ " WHERE CATEGORY NOT IN (?) "
+ " ORDER BY RANDOM() LIMIT 1 ";
sql = sql.replace("?", params);
Cursor cursor = database.rawQuery(sql, null);
Note that this method is prone to sql injection.
Another way is to create a list of ? placeholders instead of 1 placeholder and pass the list of values as an array of strings like this:
for (String param : s1.ListViewCategory) {
sb.append(",?");
}
String[] array = ListViewCategory.toArray(new String[s1.ListViewCategory.size()]);
params = sb.toString().substring(1);
String sql = "SELECT CATEGORY FROM " + tableName
+ " WHERE CATEGORY NOT IN (#) "
+ " ORDER BY RANDOM() LIMIT 1 ";
sql = sql.replace("#", params);
Cursor cursor = database.rawQuery(sql, array);
Here I get the last value of pushkey(column) by below code
String abc="value for filtering data"
String selectQuery= "SELECT * FROM " + TABLE_NAME+" ORDER BY id DESC LIMIT 1";
SQLiteDatabase db = myDbHandler.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
String str = "";
if(cursor.moveToFirst())
str = cursor.getString( cursor.getColumnIndex(COLUMN_PUSH_KEY) );
Toast.makeText(this, str, Toast.LENGTH_SHORT).show();
cursor.close();
But now I want to get last value of pushkey when fromid(column) set filter by some predefined String abc value. So how to add filter and make query ?
https://i.stack.imgur.com/77thU.png
If by last you mean ordered by ID descending then add a WHERE clause like this:
String selectQuery= "SELECT pushkey FROM " + TABLE_NAME + " WHERE fromid = 'DIX....UVa2' ORDER BY id DESC LIMIT 1"
If you just want to filter by fromid:
String selectQuery= "SELECT pushkey FROM " + TABLE_NAME + " WHERE fromid = 'DIX....UVa2'"
If you want all the columns, change to:
String selectQuery= "SELECT * FROM " + TABLE_NAME + " WHERE fromid = 'DIX....UVa2'"
Use this Java code:
String fromid = "DIX....UVa2";
String selectQuery= "SELECT * FROM " + TABLE_NAME + " WHERE fromid = ?";
SQLiteDatabase db = myDbHandler.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, fromid);
String str = "";
if(cursor.moveToFirst())
str = cursor.getString( cursor.getColumnIndex(COLUMN_PUSH_KEY) );
Toast.makeText(this, str, Toast.LENGTH_SHORT).show();
cursor.close();
Replace "DIX....UVa2" with the value that you want to filter the column fromid.
This will toast the 1st value of the results.
I want to insert records to my sqllite database but before insertion i have to check if the record exists .
I used this code but still say no such column and stopped working although the record exists .
SQLiteDatabase db = this.getReadableDatabase();
String selectQuery = "SELECT * FROM " + TABLE_TEAM + " WHERE "
+ TEAM_TABLE_NAME + " = " + name+";";
Log.e(LOG, selectQuery);
Cursor c = db.rawQuery(selectQuery, null);
if (c != null) {
return true;
}
return false;
This is the recommended way to use rawQuery():
String selectQuery = "SELECT * FROM " + TABLE_TEAM + " WHERE " + TEAM_TABLE_NAME + " = ?";
Cursor c = db.rawQuery(selectQuery, new String[] {name});
so you pass name as a parameter to the query and avoid the risk of sql injection.
In your code you only check if the Cursor object is null and not if it contains any rows which is the right thing to do.
So return the result of getCount() > 0 like this:
return c.getCount() > 0;
This will return true if the name already exists in the table.
As for the no such column error, this is something different.
First make sure that TEAM_TABLE_NAME is the correct name of the column and if it is then maybe you made changes to the names of the columns tha are not reflected to the database.
So uninstall the app from the device so the database is deleted and then rerun to recreate the database with the new names of the columns.
so i recently learn to write a code in android using sqlite and i try to select data from sqlite but this error occur
ive tried some suggestion from the internet and read my book but i didnt solve my problem
public Penyakit getPenyakit1(String namaGejal){
SQLiteDatabase db = this.getReadableDatabase();
String query = "SELECT idPen FROM " + TABLE_CONTACTS + " WHERE " +
namapen + " =\"" + namaGejal + "\"";
Cursor cursor = db.rawQuery(query,null);
Penyakit penyakit = new Penyakit();
if(cursor.moveToFirst()){
cursor.moveToFirst();
penyakit.set_nomber(Integer.parseInt(cursor.getColumnName(0)));
penyakit.set_namaPen(cursor.getColumnName(1));
penyakit.set_idPenyakit(Integer.parseInt(cursor.getColumnName(2)));
penyakit.set_namGej(cursor.getColumnName(3));
penyakit.set_idGejala(Integer.parseInt(cursor.getColumnName(4)));
cursor.close();
} else {
penyakit=null;
}
return penyakit;
}
this is logcat
Process: com.example.lordbramasta.pakar, PID: 18914
java.lang.NumberFormatException: For input string: "idPen"
at java.lang.Integer.parseInt(Integer.java:615)
at java.lang.Integer.parseInt(Integer.java:650)
at com.example.lordbramasta.pakar.DBAdapter.getPenyakit1(DBAdapter.java:79)
i expected the value of idPen get selected , thank you
Your problem is this line:
penyakit.set_nomber(Integer.parseInt(cursor.getColumnName(0)));
cursor.getColumnName(0) returns idPen as this is the name of the only column returned by your query:
SELECT idPen FROM ....
and your code is trying to cast the string "idPen" to an integer.
So getColumnName() returns the name of the column at a specified index and not the value of the column.
You should do
penyakit.set_nomber(Integer.parseInt(cursor.getString(0)));
or if the data type of the column idPen is INTEGER then:
penyakit.set_nomber(cursor.getInt(0));
Also don't try to get any other columns because your query returns only 1.
Note: remove that cursor.moveToFirst(); inside the if block because it is already executed.
Probably you need to use a ' instead of ". So, change the query to the following:
String query = "SELECT idPen FROM " + TABLE_CONTACTS + " WHERE " +
namapen + " =\'" + namaGejal + "\'";
I'm suggesting you to use SQLiteDatabase.query() instead rawQuery like this:
// Define a projection that specifies which columns from the database
// you will actually use after this query.
String[] projection = {
"idPen"
};
// Filter results WHERE "namapen" = 'namaGejal'
String selection = "namapen" + " = ?";
String[] selectionArgs = { namaGejal };
// How you want the results sorted in the resulting Cursor
String sortOrder = null; // null for default order
Cursor cursor = db.query(
TABLE_CONTACTS, // The table to query
projection, // The array of columns to return (pass null to get all)
selection, // The columns for the WHERE clause
selectionArgs, // The values for the WHERE clause
null, // don't group the rows
null, // don't filter by row groups
sortOrder // The sort order
);
// do something with the cursor
Please take a look Read information from a database
If you want to get all columns data from your TABLE_CONTACTS use SELECT * FROM
This is a simple one! yet, I am missing something. Please help me out.
Here, I am trying to fetch values by id, but not able to do so. It is returning same values even after changing id's value.
db = openOrCreateDatabase("DBSOURCE", 0, null);
Cursor cursorc = db.rawQuery("SELECT * FROM LIST WHERE ID="+id+"", null);
cursorc.moveToFirst();
int NameID = cursorc.getColumnIndex("Name");
int mobilenumberID = cursorc.getColumnIndex("MoblieNumber");
edName.setText(cursorc.getString(NameID));
edMobNum.setText(cursorc.getString(mobilenumberID));
cursorc.close();
db.close();
1-
or better to use parametrized statement
String query = "SELECT COUNT(*) FROM " + tableName + " WHERE columnName = ?";
cursor = db.rawQuery(query, new String[] {comment});
2 - use if with conditon c.moveToFirst() or c.getCount() >0 or (!c.isAfterLast())
if (c.moveToFirst()){
do{
//if you not need the loop you can remove that
id = c.getInt(c.getColumnIndex("_id"));
}
while(cursor.moveToNext());
}c.close();
Is the id column title actually "ID"? Or is that a variable that is set to "_id" (the usual column name for the primary key in an Android database)?
If the latter, your query is not right, because you are using "ID" as the literal column name. Try changing it to this:
Cursor cursorc = db.rawQuery("SELECT * FROM LIST WHERE " + ID + " = " + id, null);
or even this:
Cursor cursorc = db.rawQuery("SELECT * FROM LIST WHERE _id = " + id, null);
try using
Cursor cursorc = db.rawQuery("select * from list where ID = ?", new String[] {id+""});
try with this way
Suppose long id=5;
String[] col=new String[]{KEY_ROWID,KEY_NAME,KEY_ADDRESS}; // your column which data u want to retrive if id is same
Cursor c=db.query(DATABASE_TABLE, col, KEY_ROWID+"="+id,null, null, null, null);
if(c!=null){
c.moveToFirst();
// get data here which u want accroding to ur requirement
}
try this
Cursor cursorc = db.rawQuery("SELECT * FROM LIST WHERE ID='"+id+"'", null);