Better way to write a join query in ormlite - android

I have two tables CustomerBalance and Customer which are bound with CustomerRefId field.
I want the CustomerBalance records that are lets say greater than 100 for a field balance of this tables. I also want to include into my results the name of the particular customer that fulfills that criteria. I created the following method that works!
public List<CustomerBalance> getCustomerBalanceFilter(String filterVal) {
try {
PreparedQuery<CustomerBalance> preparedQuery = mDbHelper.getCustomerBalanceDao().queryBuilder()
.where().gt(CustomerBalance.DB_COL_CUSTOMER_BALANCE, filterVal)
.prepare();
List<CustomerBalance> result = mDbHelper.getCustomerBalanceDao().query(preparedQuery);
for(CustomerBalance alert : result) {
PreparedQuery<Customer> getCustQuery = mDbHelper.getCustomerDao().queryBuilder()
.where().eq(Customer.DB_COL_CUSTOMER_REF_ID, alert.getCustomerID())
.prepare();
List<Customer> customer = mDbHelper.getCustomerDao().query(getCustQuery);
alert.setCustomer(customer.size() == 1 ? customer.get(0) : null);
}
return result;
} catch(Exception ex) {
return null;
}
}
This methods is working, is this the best way to write such a query? or is there a more appropriate approach?

One improvement to your query is to use ORMLite's SelectArg to pass in the customer-id instead of a new query each time. Something like:
...
List<CustomerBalance> result = mDbHelper.getCustomerBalanceDao()
.query(preparedQuery);
SelectArg custIdArg = new SelectArg();
PreparedQuery<Customer> getCustQuery = mDbHelper.getCustomerDao().queryBuilder()
.where().eq(Customer.DB_COL_CUSTOMER_REF_ID, custIdArg)
.prepare();
for (CustomerBalance alert : result) {
custIdArg.setValue(alert.getCustomerID());
List<Customer> customer = mDbHelper.getCustomerDao().query(getCustQuery);
alert.setCustomer(customer.size() == 1 ? customer.get(0) : null);
}
Here are the docs for SelectArg:
http://ormlite.com/docs/select-arg
FYI, there also is an UpdateBuilder, but I don't see an easy way to turn your code above into a single UPDATE statement.

Related

Realm on Android - How to select multiple objects by list of ids (#PrimaryKey)?

I'm building an Android app with the Realm database.
I have a RealmObject subclass called Article which has an id field (it's and int and also a #PrimaryKey). I would like to pass to a query a list of ints (a Set, int[], or whatever) of article id's and retrieve only those articles.
In SQL would be like this:
SELECT *
FROM `table`
where ID in (5263, 5625, 5628, 5621)
I've seen it's possible to do this in iOS in this StackOverflow question.
How can I do this in Android? Thanks!
Edit: Just to inform, I also asked this on the GitHub repo here.
Update:
Realm 1.2.0 has added RealmQuery.in() for a comparison against multiple values. The documentation details all the available overloads. This one is the method we can use if our ids are Integers:
public RealmQuery<E> in(String fieldName, Integer[] values)
Original answer:
The answer from #ChristianMelchior returns all articles if the list of ids is empty. I want it to return an empty RealmResults<Article>. That's what I've ended up doing:
Set<Integer> articleIds = this.getArticleIds();
RealmQuery<Article> query = realm.where(Article.class);
if (articleIds.size() == 0) {
// We want to return an empty list if the list of ids is empty.
// Just use alwaysFalse
query = query.alwaysFalse();
} else {
int i = 0;
for (int id : articleIds) {
// The or() operator requires left hand and right hand elements.
// If articleIds had only one element then it would crash with
// "Missing right-hand side of OR"
if (i++ > 0) {
query = query.or();
}
query = query.equalTo("id", id);
}
}
return query.findAll();
Now realm v 1.2.0 support RealmQuery.in() for a comparison against multiple values.
The Realm Java API's doesn't support this yet unfortunately. You can follow the feature request here https://github.com/realm/realm-java/issues/841
The current work-around would be to build up the query yourself in a for-loop:
RealmResults<Article> articles = realm.allObjects(Article.class);
RealmQuery q = articles.where();
for (int id : ids) {
q = q.equalTo("id", id);
}
RealmResults<Article> filteredArticles = q.findAll();
This is the way Realm does it since 1.2.0:
public RealmQuery<E> in(String fieldName, String[] values) {
if (values == null || values.length == 0) {
throw new IllegalArgumentException(EMPTY_VALUES);
}
beginGroup().equalTo(fieldName, values[0]);
for (int i = 1; i < values.length; i++) {
or().equalTo(fieldName, values[i]);
}
return endGroup();
}
Previously this is how I did it
I just came across this post and I thought I could throw in my 2 cents on this. As much as I appreciate Christian Melchior and his answers I think in this case his answer is not working (at least in the current version).
I prefer to do it like this - I personally think it's more readable than Albert Vila's answer:
List<String> listOfIds = [..];
RealmQuery<SomeClass> query = realm.where(SomeClass.class);
boolean first = true;
for (String id : listOfIds) {
if (!first) {
query.or();
} else {
first = false;
}
query.equalTo("id", id);
}
RealmResults<SomeClass> results = query.findAll();

Why my ArrayList<String> is NOT sorted correctly?

I've been searching online and trying, but I didn't find the solution.
I have the following ArrayList:
{ Cate1, Cate3, Cate6, Cate2, ...., thru Cate10 }
I gave tried the following solutions:
public ArrayList<String> GetAllCategories_ByAscOrder() {
db = getWritableDatabase();
ArrayList<String> Category_ArrayList = new ArrayList<String>();
Cursor cursor = db.query(Category_TABLE, null, null, null, null, null, Category_List + " ASC");
if(cursor != null)
{
while(cursor.moveToNext())
{
String CATEGORY = cursor.getString(cursor.getColumnIndex(Category_List));
Category_ArrayList.add(CATEGORY);
}
}
cursor.close();
return Category_ArrayList;
}
And these:
Collections.sort(CATEGORY_LIST, new Comparator<String>(){
public int compare(String obj1, String obj2)
{
return obj1.compareToIgnoreCase(obj2);
}
});
}
//OR THIS:
Collections.sort(CATEGORY_LIST, new Comparator<String>(){
public int compare(String obj1, String obj2)
{
return obj1.compareTo(obj2);
}
});
}
//OR THIS:
Collections.sort(CATEGORY_LIST, String.CASE_INSENSITIVE_ORDER);
But ALL of them gave me the same sorting results:
Cate1, Cart10, Cate2, Cate3,, etc.... Cate9
I want the sorted list to be like this:
Cate1 thru Cate10
Can someone please guide me on how I can achieve this?
Thank you very much
Edit:
I forgot to mention that I let the users freely name their Category Names.
do like this :
Collections.sort(list , new Comparator<String>(){
public int compare( String a, String b ){
// if contains number
if( a.substring(4).matches("\\d+") && b.substring(4).matches("\\d+")) {
return new Integer( a.substring(4) ) - new Integer( b.substring(4) );
}
// else, compare normally.
return a.compareTo( b );
}
});
Its sorted by lexicographical order.
If you want it sorted like that, you should switch to using two digits,
eg. Cate01, Cate02, ...
Note that this happens in Windows/Linux filesystems too (if you have numbered files in a folder).
Technically, the results you got are correct - Cart10 alphabetically comes before Cart2 (since 1 comes before 2).
Try adding leading 0s to your numbers before sorting: Cart01, Cart02, etc - though you'll need to pad with leading zeros to make sure you cover the largest you expect your list to get (if it'll be over 100 elements, you'll need more zeros).
Alternatively, why not just store it as ArrayList<Integer> and prepend with "Cart" when you go to output the results? How you ultimately solve this depends on what you want to use the values for...

Multiple Query Condition in Android using ORMLITE

i want to make a simple query, with multiple conditions
I use OrmLite to map entity object.
Now I want to search for an object into my table.
Supposing i have a Person entity that maps PERSON table, what I want to do is to initialize an object with some parameters and search it.
Suppose a function searchPerson(Person oPerson)
If i pass an object OPerson like this
Id = null
Name = John
Age = null
Sex = male
Is possible to write a query to reach that goal? Something like this pseudo-code
pers = (from p in db.Table<Person>()
where (if OPerson.Id !=null) p.Id==OPerson.Id}
AND {(if OPerson.Name !=null) p.Name.Contains(OPerson.Name)}
AND {(if condition) where-contion}
select p).ToList();
I know that i can do multiple query in this way
list=PersonDao.queryBuilder().where().eq("name",OPerson.name)
.and().eq("sex",OPerson.sex").query();
but I want also to check if the value exists
where (if OPerson.Id !=null) p.Id==OPerson.Id}
#ArghArgh is close but doesn't have the ANDs right. The problem is that the AND statements are conditional on whether there were any previous statements. I'd do something like:
QueryBuilder<Person, Integer> queryBuilder = dao.queryBuilder();
Where<Person, Integer> where = queryBuilder.where();
int condCount = 0;
if (oPerson.id != null) {
where.eq("id", oPerson.id);
condCount++;
}
if (oPerson.name != null) {
where.like("name", "%" + oPerson.name + "%");
condCount++;
}
...
// if we've added any conditions then and them all together
if (condCount > 0) {
where.and(condCount);
}
// do the query
List<Persion> personList = queryBuilder.query();
This makes use of the where.and(int) method which takes a number of clauses on the stack and puts them together with ANDs between.
I think that you must use the QueryBuilder.
Try something like this
QueryBuilder<Person, Integer> queryBuilder = PersonDao.queryBuilder();
// get the WHERE object to build our query
Where<Person, String> where = queryBuilder.where();
if(oPerson.Name!=null)
where.like("Name", "%"+oPerson.Name+"%");
// and
where.and();
if(Person.Sex!=null)
where.like("Sex", "%"+oPerson.sex+"%");
PreparedQuery<Person> preparedQuery = queryBuilder.prepare();
Than you can call it in this way
List<Person> list = PersontDao.query(preparedQuery);

OrmLite: Advanced where logic

I have these tables in an Android based application where I'm using OrmLite for the database management.
What I want to have an x number of array list depending on how many of the product type FOLDER I have.
So in this case I want to a list of products where the productId equals parentId.
So I want a list where
if(productType = FOLDER) {
if(productId = parentId){
//add product
}
}
Basically what I want to end up with, in this case three lists with each containing a list of products where parentId is the same for every product.
I've tried many things, and some works better than others, but a code I want to run actually throws a nullpointer.
DatabaseHelper dbHelper = getHelper();
List<Product> productsParents = null;
try {
Dao<Product, Integer> dao = dbHelper.getDao();
PreparedQuery<Product> prepQu = dao.queryBuilder().where()
.eq("parentId", dao.queryBuilder().selectColumns("productId").where()
.eq("productType", ProductType.FOLDER).prepare()).prepare();
productsParents = dao.query(prepQu);
} catch (SQLException e) {
...
}
This code isn't working because productParents returns null, and it does not do what I want, even though it's a slight hint. If someone know how to do this in code that would be sufficient also, or more likely a mix of java and ormlite.
Have you had a chance to RTFM around building queries? The ORMLite docs are pretty extensive:
http://ormlite.com/docs/query-builder
Your problem is that a prepared query cannot be an argument to the eq(...) method. Not sure where you saw an example of that form.
So there are a couple ways you can do this. The easiest way is to do a different query for each productType:
Where<Product, Integer> where = dao.queryBuilder().where();
where.eq("parentId", parentId).and().eq("productType", ProductType.FOLDER);
productsParents = where.query();
// then do another similar query again with ProductType.PRODUCT, ...
If you want to do just one query then you can get all products that match the parentId and then separate them using code:
Where<Product, Integer> where = dao.queryBuilder().where();
where.eq("parentId", parentId);
productsParents = where.query();
List<Product> productFolders = new ArrayList<Product>();
List<Product> productProducts = new ArrayList<Product>();
...
for (Product product : productsParents) {
if (product.getProductType() == ProductType.FOLDER) {
productFolders.add(product);
} else if (product.getProductType() == ProductType.PRODUCT) {
productProducts.add(product);
} else ...
}

i want to compare names in two different tables and then equal get details

i have two different tables.I want to compare the names in two tables,if both the names are equal then i want to get the details.how can i do that? please help me.
Here is the code:
Cursor cr=mDbManager.fetchnewcustomerdata();
Cursor cr1 = mDbManager.fetchinvoicecustomerdata();
cr1.moveToFirst();
//String address;
while (!(cr1.isAfterLast())) {
String name = cr1.getString(cr1.getColumnIndex("icstname"));
if(name.equals(cr.getString(cr.getColumnIndex("cname"))))
{
Toast.makeText(this,"equal",1000).show();
}
String address = cr1.getString(cr1.getColumnIndex("caddress"));
map.put(name, address);
nameAList.add(cr1.getString(cr1.getColumnIndex("icstname")));
cr1.moveToNext();
}
mDbManager.close();
}
I think two ways it is possible
1) Either you need to establish relationship between those tables using the name column you are thinking of same between two tables.
2) Two separate queries to database, where condition for both queries will be the name
You can use CursorJoiner
http://developer.android.com/reference/android/database/CursorJoiner.html
Firstly, the names are ordered .
Then, sort it as the following sample:
while( !eofInTable1 && !eofInTable2) {
String name1 = getFieldFromTable1();
String name2 = getFiledFromTable2();
int tmpResult = name1.compareTo(name2);
if(tmpResult == 0) {
doYourAction();
table1.moveToNext();
table2.moveToNext();
}
else if( tmpResult == -1) {
table1.moveToNext();
}
else {
table2.moveToNext();
}
}

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