I am pretty new to SQLite databases, so please forgive me...
I have a database with integer values. When updating a row in the database using the code below, there is somehting I don't understand. whereArgs is of type String[], though the values you are looking for are integers, so I would expect that one should pass in a int[].
SQ.update(table, values, whereClause, whereArgs)
Where do I go wrong?
Example code (hypothetical):
public void changeOneIntoTwo(DatabaseOperations dop) {
SQLiteDatabase SQ = dop.getWritableDatabase();
String selection = "ValuesColumn = ?";
String[] args = {"1"};
ContentValues cv = new ContentValues();
cv.put("ValuesColumn", 2);
SQ.update("MyTable", cv, selection, args);
}
selection is the condition that you put in where clause of Sql query and args is what replaced by "?" of selection .
for example : lets assume you need your sql query select * from Mytable where ValuesColumn ='1' and Name = 'MVB'. so in this case
String selection = "ValuesColumn = ? AND Name = ?";
String[] args = {"1","MVB"};
Related
I am trying to program a get a query that will show data from COURSE table if the values are :
course_id=0
or
semester_id=0
or
level_id=0
or
level_code=Select level
or
grade=Grade
So any rows that have any of the values above should be showed :
public List<Courses> getListCourseError() {
Courses courses = null;
List<Courses> coursesList = new ArrayList<>();
openDatabase();
Cursor cursor = mDatabase.rawQuery("SELECT * FROM COURSES WHERE semester_id=0 OR level_id=0 OR level_code=Select level OR grade=Grade", null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
courses = new Courses(cursor.getInt(0), cursor.getInt(1), cursor.getString(2), cursor.getInt(3), cursor.getInt(4), cursor.getString(5), cursor.getInt(6), cursor.getString(7), cursor.getInt(8), cursor.getInt(9));
coursesList.add(courses);
cursor.moveToNext();
}
cursor.close();
closeDatabase();
return coursesList;
}
Thanks
I believe that you issue is that string values have to be enclosed in quotes. You are also not including course_id is 0.
So instead of "SELECT * FROM COURSES WHERE semester_id=0 OR level_id=0 OR level_code=Select level OR grade=Grade"
use :-
"SELECT * FROM COURSES WHERE course_id=0 OR semester_id=0 OR level_id=0 OR level_code='Select level' OR grade='Grade'"
However the above is a candidate for SQL injection so really you should be utilising the selection args (2nd parameter), which will properly enclose strings on your behalf. So the more correct solution would be to utilise :-
String[] selectionargs = new String[]{"0","0","0","Select level", "Grade"};
Cursor cursor = mDatabase.rawQuery("SELECT * FROM COURSES WHERE course_id=? semester_id=? OR level_id=? OR level_code=? OR grade=?", selectionargs);
However, it is recommended to only use the rawQuery method when need and that the conveniece query method be used. This would be :-
String whereclause = "course_id=? OR semester_id=? OR level_id=? OR level_code=? or grade=?";
String[] whereargs = new String[]{"0","0","0","Select level", "Grade"};
Cursor cursor = mDatabase.query(
"COURSES",
null, //<<<< all columns (else String[] of columns)
whereclause, //<<<< WHERE clause without the WHERE keyword
whereargs, //<<<< arguments to replace ?'s
null, //<<<< GROUP BY clause
null, //<<<< HAVING clause
null //<<<< ORDER BY clause
);
Notes
- null results in the respective parameter to be ignored/defaulted (table name cannot be null). e.g. columns (2nd parameter) as null defaults to ALL columns i.e. *.
there are a number of different query method signatures. See SQLiteDatabase
The code above is in-principle code and has not been tested so there may be some errors.
I am trying to update a specific column in my record within SQLite - the object has various attributes, but I just want to update a single field within that row. Here are my codes:
public boolean updateFavorite(String email, int isFavorite){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues args = new ContentValues();
args.put(EMAIL, email);
args.put(IS_FAV, isFavorite);
int i = db.update(TABLE_FAVORITES, args, EMAIL + "=" + email, null);
return i > 0;
}
I am using the email for my where clause, i.e update record from favorites, set isFavorite to (given value) where email is (passed in value).
There is a problem with my query, which was caught by logcat, as shown below
android.database.sqlite.SQLiteException: near "#sjisis": syntax error (code 1): , while compiling: UPDATE Favorites SET email=?,isFavorite=? WHERE email=sjkshs#sjisis.com
Can anyone help me identify what is wrong with my codes to produce this error?
P.S my FavoriteObject class has other attributes other than just email and isFavorite, but in this case I am not trying to update them at all
Try to make email in where clause be argument too, i try to change your code but didn't test yet :
public boolean updateFavorite(String email, int isFavorite){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values= new ContentValues();
values.put(EMAIL, email);
values.put(IS_FAV, isFavorite);
//add arguments for where clause
String[] args = new String[]{email};
int i = db.update(TABLE_FAVORITES, values, "EMAIL=?", args);
return i > 0;
}
Looks like it's complaining about the email address, perhaps the #.
try
int i = db.update(TABLE_FAVORITES, args, EMAIL + "= ' " + email + "'", null);
ie. single quotes around the email address.
I have table contains columns id, name, profession, age, hobby, country, sex. Now I want to update the fields where sex is female and age is 30. All the fields are text (String). First, I am counting all the rows then running a loop to update the rows. Loop is running as per the total rows but rows are not updated... WHY? Where I have done the mistake? Here is my code:
METHODS FOR ANDROID SQLITE DATABASE QUERY:
public void updateUser(String newProfession, String newCountry, String sx, String ag) {
SQLiteDatabase db = this.getWritableDatabase();
String query = "UPDATE "+TABLE_USER+" SET "+KEY_PROFESSION+"='"+newProfession+"', "+KEY_COUNTRY+"='"+newCountry+"' WHERE "+KEY_SEX+"='"+sx+"' AND "+KEY_AGE+"='"+ag+"'";
Cursor cursor = db.rawQuery(query, null);
cursor.close();
db.close();
}
public int countAll() {
String countQuery = "SELECT * FROM " + TABLE_USER;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int cnt = cursor.getCount();
cursor.close();
db.close();
return cnt;
}
CALLING THE METHODS
public void updateUsersClicked(View view) {
int allData = db.countAll();
for (int i = 0; i < allData; i++) {
db.updateUser("SENIOR ENGINEER", "CANADA", "female", "30");
System.out.println("T H I S I S T H E R E S U L T: " + i);
}
}
Use execSQL() and not rawQuery() for updates.
rawQuery() just compiles the SQL and requires one of the moveTo...() methods on the returned Cursor to execute it. execSQL() both compiles and runs the SQL.
Also consider using ? parameters with bind args in your SQL to avoid escaping special characters and being vulnerable to SQL injection.
You don't need to do the for loop
a single QSL "Update" query is enough if you want to update All the female with age 30.
If you are new to SQL you can view a simple example here:
Simple SQL Update example
If you want to do something else - please edit your question
I have a problem with to update a varchar in the sqlite database in java.
when I run this source, than I get a error.
I want String a to update to String b.
This is my source:
public void onClick (View v){
String a = "Test1";
String b = "Test2";
db = openOrCreateDatabase("MyDB", MODE_PRIVATE, null);
ContentValues values = new ContentValues();
values.put("Level1", b);
db.update("Game", values, a, null);
db.close();
}
And this is my Error:
Error updating Level1=Test2 using update Game SET Level1=? WHERE Test1.
can someone help me?
Thanks!
I'm not 100% sure what you are trying to achieve, however, you added a as a where clause and did not provide any arguments, so consequently you got the SQL statement shown in the error.
From the API:
public int update (String table, ContentValues values,
String whereClause, String[] whereArgs)
This one works ...
db = openOrCreateDatabase("MyDB", MODE_PRIVATE, null);
ContentValues values = new ContentValues();
values.put("Level1", b);
db.update("Game", values, "Level1=?", new String[] {a} );
db.close();
... if this is the resulting SQL you want to execute:
update Game SET Level1=? WHERE Level1 = 'Test1'
update Game SET Level1=? WHERE Test1.
Where Test1 is.. what? Where is the conditional part of your update statement. It's expecting something like:
update Game SET Level1=? WHERE ColumnName='Test1'
Taken from this website:
If the UPDATE statement does not have a WHERE clause, all rows in the table are modified by the UPDATE. Otherwise, the UPDATE affects only those rows for which the result of evaluating the WHERE clause expression as a boolean expression is true.
A String on it's own is in no way a boolean expression.
I have a database table with multiple columns
I use custom List<> and populate it from database
What i want to do is filter what will go into the list from database depending on user input
for example if i had a table like this:
name|phone|date|address
User can specify any filter(by name, by phone, by date... or all of it) and only items that matches all criteria will go into the list
Is there a way to do this?
Method that returns all items from database
public List<MoviesDatabaseEntry> getAllMovies(String table)
{
List<MoviesDatabaseEntry> lists = new ArrayList<MoviesDatabaseEntry>();
// Select All Query
String selectQuery = "SELECT * FROM " + table;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst())
{
do {
MoviesDatabaseEntry list = new MoviesDatabaseEntry();
list.set_id(Integer.parseInt(cursor.getString(0)));
list.set_title(cursor.getString(1));
list.set_runtime(cursor.getString(2));
list.set_rating(cursor.getDouble(3));
list.set_genres(cursor.getString(4));
list.set_type(cursor.getString(5));
list.set_lang(cursor.getString(6));
list.set_poster(cursor.getString(7));
list.set_url(cursor.getString(8));
list.set_director(cursor.getString(9));
list.set_actors(cursor.getString(10));
list.set_plot(cursor.getString(11));
list.set_year(cursor.getInt(12));
list.set_country(cursor.getString(13));
list.set_date(cursor.getInt(14));
// Adding to list
lists.add(list);
} while (cursor.moveToNext());
}
// return list
db.close();
cursor.close();
return lists;
}
You can filter the entries you get in the SQL query you are building in this line:
String selectQuery = "SELECT * FROM " + table;
To filter the dataset your retrieve, you would add a WHERE clause to it. When you would, for example, only want those entries where the rating is over 3, you would change this to:
String selectQuery = "SELECT * FROM " + table + " WHERE rating > 3";
SQL is a very powerful language which offers a lot of possibilities. It's an essential skill when you work with relational databases. When you want to learn it, I can recommend you the interactive tutorial website http://sqlzoo.net/
You have to change your database query for getting specific data from the query.
You have one function that returns all rows from database like so: getAllMovies(String table)
Here you are using:
String selectQuery = "SELECT * FROM " + table;
Make a new function like this:
public List<MoviesDatabaseEntry> getSelectedMovies(String table)
{
List<MoviesDatabaseEntry> lists = new ArrayList<MoviesDatabaseEntry>();
Cursor cursor = db.query(true, TABLE_NAME, new String[] { <your row names> },
**check condition(as string)**, null,
null, null, null, null);
...
}
Now just call this function when required with your specific query string
Make as many functions as you want!