My android app has 2 tables Projects and Tasks.
Each Project can have multiple Tasks.
Like below
Now I want to sum up all proportion values of the single task table
I did it.. but the issue is its adding proportion values from all task tables !
The cursor I coded is as follows
public int sumproportion(long projectId){
int value = 0;
int p = 0;
Cursor cu = mDatabase.rawQuery("SELECT * FROM " + DBHelper.TABLE_TASKS, null);
ArrayList temp = new ArrayList();
if (cur != null) {
if (cur.moveToFirst()) {
do {
temp.add(cur.getString(cur.getColumnIndex("proportion"))); // "Title" is the field name(column) of the Table
} while (cur.moveToNext());
}
}
Object ia[] = temp.toArray();
for(int i=0; i<ia.length; i++)
{
p = Integer.parseInt((String) ia[i]);
value = value + p;
}
System.out.println("Value is: " + value);
return value;
}
When I added cursor as below
Cursor cur = mDatabase.query(DBHelper.TABLE_TASKS, mAllColumns,
DBHelper.COLUMN_TASK_PROJECT_ID + " ="+String.valueOf(projectId),
null, null, null, null);
It doesn't add anything. Can any one help fix it please?
First of all, you can just use query like this SELECT SUM(proportion) from TABLE_TASK. proportion should have numeric type.
Secondly, verify that your Cursor return any rows. Probably you pass wrong projectId if there no rows.
Related
I am retrieving data according to dates but when running my app its shows nothing.
Here's my code :
SQL QUERY :
private Cursor getAllCurrentData()
{
String[] selectArg = new String[]{};
return db.query(Db_Contract.Db_Fieds.TABLE_NAME,
null ,
Db_Contract.Db_Fieds.DATE+ "= 2018-11-10",
selectArg,
null,
null,
Db_Contract.Db_Fieds.TIMESTAMP);
}
Displaying Data :
private void totalMoney()
{
Cursor cursor = getAllCurrentData();
double sum = 0.000d;
double getMoney;
while (cursor.moveToNext()) {
getMoney = cursor.getDouble(cursor.getColumnIndex(Db_Contract.Db_Fieds.MONEY));
sum += getMoney;
}
total.setText("Total money spent: " +sum);
}
I am new to Android Programming. Where I am doing wrong ?. Please correct me
First make sure you are connected to database and cursor returned by db.query() is not empty/null. Then Iterate over cursor like
private void totalMoney()
{
openDatabase();
Cursor cursor = getAllCurrentData();
cursor.moveToFirst();
double getMoney = 0;
while (!cursor.isAfterLast()) {
getMoney = cursor.getDouble(cursor.getColumnIndex(Db_Contract.Db_Fieds.MONEY));
sum += getMoney;
cursor.moveToNext();
}
total.setText("Total money spent: " + sum );
closeDatabase();
}
I want to get number of rows inside a table using a SELECT COUNT(*) as nb query. Then when I want to get the result by using cursor.getInt(0) then the app crashed ! So I replaced my code with this :
public int getParcelleCount() {
String countQuery = "SELECT * FROM " + T_PARCELLE;
Cursor cursor = bd.rawQuery(countQuery, null);
int nb = 0;
if (cursor != null) {
nb = cursor.getCount();
}
cursor.close();
return nb;
}
And it works ! So why is the first option wrong ?
Your previous code did not work because you were trying to get values without moving to first. You have check for not null that was correct. But it was throwing Cursor Index Out Of Bounds Exception(You can search on internet). So you have to move cursor to first and then try to get values.
Try below code.
String countQuery = "SELECT COUNT(*) AS NB FROM " + T_PARCELLE;
Cursor cursor = bd.rawQuery(countQuery, null);
int nb = 0;
if (cursor.moveToFirst()) {
do
{
nb = cursor.getInt(0);
}while(cursor.moveToNext());
}
cursor.close();
return nb;
I'm trying to implement dynamic queries in my Android app, to let the users search according to some criteria. In this case I'm trying to search simply by an integer value. Here's my attempt:
...
public String[][] listarNegocio(int idProyecto,
int minimo,
int maximo)
{
String[][] arrayDatos = null;
String[] parametros = {String.valueOf(idProyecto)};
Cursor cursor = null;
cursor = querySQL("SELECT *" +
" FROM negocio" +
" WHERE ? in (0, id_proyecto)", parametros);
if(cursor.getCount() > 0)
{
int i = minimo - 1;
arrayDatos = new String[maximo - minimo + 1][20];
while(cursor.moveToNext() && i < maximo)
{
// Here I fill the array with data
i = i + 1;
}
}
cursor.close();
CloseDB();
return(arrayDatos);
}
public Cursor querySQL(String sql, String[] selectionArgs)
{
Cursor oRet = null;
// Opens the database object in "write" mode.
db = oDB.getReadableDatabase();
oRet = db.rawQuery(sql, selectionArgs);
return(oRet);
}
...
I tested this query using SQLFiddle, and it should return only the rows where the column id_proyecto equals the parameter idProyecto, or every row if idProyecto equals 0. But it doesn't return anything. If I remove the WHERE clause and replace "parametros" with "null", it works fine.
Additionally, I need to search by text values, using LIKE. For example, WHERE col_name LIKE strName + '%' OR strName = ''. How should I format my parameters and the query to make it work?
You should do one query for each case. For an id that exists, do SELECT * FROM negocio WHERE id_proyecto = ?. For an id that doesn't exist (I'm assuming 0 isn't a real id), just query everything with SELECT * FROM negocio.
Code should be something like this:
if(parametros[0] != 0){
cursor = querySQL("SELECT *" +
" FROM negocio" +
" WHERE id_proyecto = ?", parametros);
} else {
cursor = querySQL("SELECT *" +
" FROM negocio", null);
}
Regarding your second question, it depends on what you're looking for, you could use LIKE '%param%' or CONTAINS for occurrences in between text, LIKE param for partial matches or just = param if you're looking an exact match.
I have researched a handful of other forums with a similar topic and I have yet to find an answer to this frustrating issue. I am trying to use an array to check if a column in my database has one of the multiple values in the array. My cursor is as follows:
public Cursor notificationQuery(String geoIds) {
Log.e("STRINGS", geoIds);
return mDb.query(Constants.TABLE_POI_NAME,
new String[]{Constants.TABLE_COLUMN_ID, Constants.TABLE_COLUMN_POI_NAME,
Constants.TABLE_COLUMN_LATITUDE, Constants.TABLE_COLUMN_LONGITUDE,
Constants.TABLE_COLUMN_GEO_ID},
Constants.TABLE_COLUMN_GEO_ID + " IN (?)",
new String[]{geoIds},
null, null, null, null);
}
geoIds is currently an array of two values which has been converted into a string. The logged value of that string is below:
21007b0f-6b20-4eff-9a76-b412db8daa2e,26c695d6-6cb4-4c74-9933-281813a06fd9
Those are to separate Id values separated by a comma. When I test each one individually using "= ?" instead of "IN (?)" I get a proper match with the database and my cursor returns a value. However, when combined my cursor returns nothing when it should return two rows from the database. Please help me solve this issue! Thanks!
Consider a function String makePlaceholders(int len) which returns len question-marks separated with commas, then:
public Cursor notificationQuery(String geoId1,String geoId2) {
//assume we split this geoIds to 2 different values. you need to have 2 strings no 1
String[] ids = { geoId1, geoId2 }; // do whatever is needed first depends on your inputs
String query = "SELECT * FROM "+ Constants.TABLE_POI_NAME + " WHERE "+
Constants.TABLE_COLUMN_GEO_ID +" IN (" + makePlaceholders(names.length) + ")";
return mDb.rawQuery(query, ids); // ids is the table above
}
Here is one implementation of makePlaceholders(int len):
String makePlaceholders(int len) {
if (len < 1) {
// It will lead to an invalid query anyway ..
throw new RuntimeException("No placeholders");
} else {
StringBuilder sb = new StringBuilder(len * 2 - 1);
sb.append("?");
for (int i = 1; i < len; i++) {
sb.append(",?");
}
return sb.toString();
}
}
Or more simply, use the geoIds variable directly:
public Cursor notificationQuery(String geoIds) {
Log.e("STRINGS", geoIds);
return mDb.query(Constants.TABLE_POI_NAME,
new String[]{Constants.TABLE_COLUMN_ID, Constants.TABLE_COLUMN_POI_NAME,
Constants.TABLE_COLUMN_LATITUDE, Constants.TABLE_COLUMN_LONGITUDE,
Constants.TABLE_COLUMN_GEO_ID},
Constants.TABLE_COLUMN_GEO_ID + " IN (" + geoIds + ")",
null, null, null, null, null);
}
This approach is less secure but will likely give you the result you expect.
I am populating AChartEngine from sqlite database and I need all of the data to be displayed. The problem I'm having is when I delete a record the graph series stops populating at the deleted record. I need to find a way to skip over deleted/empty records and continue populating my graph. I need it to do it the same way listview skips over deleted records and keeps on displaying all rows. I am very new to a lot of this and am having a very difficult time with this. I have tried to write if statements in order to skip deleted/empty rows but nothing seems to work. Thank you for helping!
in my graphing activity:
for (int i = 1; !c.isAfterLast(); i++) {
String value1 = db.getValue1(i);
String value2 = db.getValue2(i);
c.moveToNext();
double x7 = Double.parseDouble(value1);
double y7 = Double.parseDouble(value2);
myseries.add(x7, y7);
}
I am getting error: CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
If I surround with try and catch it will populate rows up until the deleted record.
"EDIT"
in my sqlite database:
public String getValue1(long l) {
String[] columns = new String[]{ EMP_DEPT };
Cursor c = db.query(EMP_TABLE, columns, EMP_ID + "=" + l, null, null, null, null);
if (c != null){
c.moveToFirst();
String value1 = c.getString(0);
return value1;
}
return null;
}
public String getValue2(long l) {
String[] columns = new String[]{ EMP_DATE1 };
Cursor c = db.query(EMP_TABLE, columns, EMP_ID + "=" + l, null, null, null, null);
if (c != null){
c.moveToFirst();
String value2 = c.getString(0);
return value2;
}
return null;
}
Your issue is that your safety net for commands on rows that don't exist is to use if (c != null){ and then perform your commands inside that block, but a Cursor request from a query will never come up null, it will instead result in a cursor object with no rows.
A more appropriate solution to use this as your safety net instead if (c.moveToFirst()){ Because the method itself returns a boolean for if the method actually carried itself out in the first place - true if it moved and false if not (which occurs when there's no rows to move into). another check, if you wish, would be to see how many rows the cursor has with c.getCount().
Additionally, you should combine your methods so that you don't make redundant queries to the database:
public String[] getValues(long l) {
String[] results = new String[2];
String[] columns = new String[]{ EMP_DEPT, EMP_DATE1 };
Cursor c = db.query(EMP_TABLE, columns, EMP_ID + "=" + l, null, null, null, null);
if (c.moveToFirst()) {
results[0] = c.getString(0);
results[1] = c.getString(1);
} else {
Log.d("GET_VALUES", "No results formed from this query!");
}
return results;
}
You should use a single query to get all values at once:
SELECT Date1 FROM MyTable WHERE id BETWEEN 1 AND 12345
or:
db.query(EMP_TABLE, columns, EMP_ID + " BETWEEN 1 AND " + ..., ...);
Then missing values will just not show up when you iterate over the cursor.