find data from a table

General
1

hi

i want to find data from a table i created.
for example : i have “messages” table and i want to get all the data/values of the column “content” where the data/value of column “chatName” equals to “x” (some name).
i know i can search with “whereClause”, but i don’t know what data the map “BackendlessCollection<Map> foundContacts” gives me, and how i can use it for taking related details from the table (like my example).
I’ll be glad if you answer me

2

Hello Glen,

What version of Backendless do you use: v3 or v4?
What language do you use?

Regards, Olga

3

You can find the examples here (e.g. finding all contacts from the Contact table where the value of the “age” property equals 47)

Regards, Olga

4

hi

i’m using v3 and java (android studio)

5

but i don’t know how i take the data from the map “BackendlessCollection<Map> foundContacts”.

i want to get data from a column where in another column the value equals to my query.

6

The BackendlessCollection you receive is probably of type:

BackendlessCollection&lt;Map&lt;String, Object&gt;>

The key is the column name (String), the value is the whatever type you have in that column’s value (e.g. Integer for INT, String for STRING and TEXT, Map<String, Object> for RELATIONS).

I suppose the code you’re looking for is:

foundContacts.get( "yourColumnName" );

which will return the value of the specified column.

Regards, Olga

7

=========================This is get all data=========================



private List&lt;QuoteFromUser&gt; getAllQuoteOfUserFromSever() {
final List&lt;QuoteFromUser&gt; mQuoteList = new ArrayList&lt;&gt;();
final Integer[] size = {0};
final DataQueryBuilder queryBuilder = DataQueryBuilder.create();
queryBuilder.setSortBy("created DESC");
Backendless.Data.of(Constants.TABLE_USER).getObjectCount(new AsyncCallback&lt;Integer&gt;() {
@Override
public void handleResponse(Integer integer) {
size[0] = integer;
if (size[0] > 0) {
Random random = new Random();
// queryBuilder.setPageSize(size[0]).setOffset(random.nextInt(0));
Backendless.Persistence.of(Constants.TABLE_USER).find(queryBuilder, new AsyncCallback&lt;List&lt;Map&gt;>() {
@Override
public void handleResponse(List&lt;Map&gt; response) {
for (int i = 0; i < response.size(); i++) {
QuoteFromUser quoteFromUser = new QuoteFromUser();
quoteFromUser.setUserQuoteId(response.get(i).get("objectId").toString());
quoteFromUser.setUserQuoteCategoryName(response.get(i).get("userQuoteCategoryName").toString());
quoteFromUser.setUserTimeCreated(response.get(i).get("created").toString());
quoteFromUser.setUserQuoteContent(response.get(i).get("userQuoteContent").toString());
quoteFromUser.setUserQuoteAuthorName(response.get(i).get("userQuoteAuthorName").toString());
quoteFromUser.setUserQuoteDevice(response.get(i).get("userQuoteDevice").toString());
quoteFromUser.setUserQuoteLocation(response.get(i).get("userQuoteLocation").toString());
quoteFromUser.setUserQuoteCommentCount(Integer.parseInt(response.get(i).get("userQuoteCommentCount").toString()));
quoteFromUser.setUserQuoteShareCount(Integer.parseInt(response.get(i).get("userQuoteShareCount").toString()));
quoteFromUser.setUserQuoteLikeCount(Integer.parseInt(response.get(i).get("userQuoteLikeCount").toString()));
mQuoteList.add(quoteFromUser);
}
}
@Override
public void handleFault(BackendlessFault fault) {
Toast.makeText(getApplicationContext(), getString(R.string.loading_error), Toast.LENGTH_SHORT).show();
}
});
} else {
// Toast.makeText(getApplicationContext(), getString(R.string.no_data_or_no_connect), Toast.LENGTH_SHORT).show();
}
}
@Override
public void handleFault(BackendlessFault backendlessFault) {
// Toast.makeText(MainActivity.this, backendlessFault.toString(), Toast.LENGTH_SHORT).show();
}
});
return mQuoteList;
}

*This is method to get data of column



final List&lt;Quote&gt; mQuoteList = new ArrayList&lt;&gt;();
final Integer[] size = {0};
final DataQueryBuilder queryBuilder = DataQueryBuilder.create();
queryBuilder.setWhereClause("quoteAuthorName = '" + author.getAuthorName() + "'");
Backendless.Data.of(Constants.TABLE_QUOTE).getObjectCount(queryBuilder, new AsyncCallback&lt;Integer&gt;() {
@Override
public void handleResponse(Integer integer) {
size[0] = integer;
if (size[0] > 0) {
queryBuilder.setPageSize(size[0]).setOffset(0);
Backendless.Persistence.of(Constants.TABLE_QUOTE).find(queryBuilder, new AsyncCallback&lt;List&lt;Map&gt;>() {
@Override
public void handleResponse(List&lt;Map&gt; response) {
for (int i = 0; i < size[0]; i++) {
Quote quote = new Quote();
quote.setQuoteId(response.get(i).get("objectId").toString());
quote.setQuoteCategoryName(response.get(i).get("quoteCategoryName").toString());
quote.setQuoteContent(response.get(i).get("quoteContent").toString());
quote.setQuoteAuthorName(response.get(i).get("quoteAuthorName").toString());
quote.setQuoteTimeCreated(response.get(i).get("created").toString());
mQuoteList.add(quote);
}
AdapterQuote adapterQuote = new AdapterQuote(context, mQuoteList);
lsvReadQuoteWhereClause.setAdapter(adapterQuote);
linearLayoutLoadingView.setVisibility(View.GONE);
tvNameOfClause.setText(author.getAuthorName() + " - " + mQuoteList.size());
HashMap mCategory = new HashMap();
mCategory.put("objectId", author.getAuthorId());
mCategory.put("authorQuoteCount", mQuoteList.size());
Backendless.Persistence.of(Constants.TABLE_AUTHOR).save(mCategory, new AsyncCallback&lt;Map&gt;() {
@Override
public void handleResponse(Map response) {
Log.i("SET AUTHOR QUOTE COUNT", "DONE ===========================");
}
@Override
public void handleFault(BackendlessFault fault) {
}
});
}
@Override
public void handleFault(BackendlessFault fault) {
Toast.makeText(context, R.string.loading_error, Toast.LENGTH_SHORT).show();
}
});
} else {
Toast.makeText(context, R.string.no_quote, Toast.LENGTH_SHORT).show();
dialog.cancel();
}
}
@Override
public void handleFault(BackendlessFault backendlessFault) {
Toast.makeText(context, R.string.loading_error, Toast.LENGTH_SHORT).show();
}

+++++++++++++++This is method to search++++++++++++++++++





private void getAuthorWithString(String inputContent) {
final DataQueryBuilder queryBuilder = DataQueryBuilder.create();
queryBuilder.setSortBy("created DESC");
String whereClause = "authorName LIKE '%" + inputContent + "%'";
queryBuilder.setWhereClause(whereClause);
Backendless.Persistence.of(Constants.TABLE_AUTHOR).find(queryBuilder, new AsyncCallback&lt;List&lt;Map&gt;>() {
@Override
public void handleResponse(List&lt;Map&gt; response) {
for (int i = 0; i < response.size(); i++) {
Author author = new Author();
author.setAuthorId(response.get(i).get("objectId").toString());
author.setAuthorName(response.get(i).get("authorName").toString());
author.setAuthorImage(response.get(i).get("authorImage").toString());
author.setAuthorBirthday(response.get(i).get("authorBirthday").toString());
author.setAuthorNationality(response.get(i).get("authorNationality").toString());
author.setAuthorBiography(response.get(i).get("authorBiography").toString());
author.setAuthorWikipedia(response.get(i).get("authorWikipedia").toString());
author.setAuthorShareCount(Integer.parseInt(response.get(i).get("authorShareCount").toString()));
author.setAuthorCommentCount(Integer.parseInt(response.get(i).get("authorCommentCount").toString()));
author.setAuthorLikeCount(Integer.parseInt(response.get(i).get("authorLikeCount").toString()));
author.setAuthorQuoteCount(Integer.parseInt(response.get(i).get("authorQuoteCount").toString()));
authorList.add(author);
}
linearLayout.setVisibility(View.GONE);
if (authorList.size() == 0) {
Toast.makeText(getApplicationContext(), getString(R.string.no_data), Toast.LENGTH_SHORT).show();
} else {
AdapterAuthorImage adapterAuthorImage = new AdapterAuthorImage(SearchQuoteActivity.this, authorList);
lsvSearch.setAdapter(adapterAuthorImage);
}
}
@Override
public void handleFault(BackendlessFault fault) {
// Toast.makeText(getApplicationContext(), getString(R.string.no_data), Toast.LENGTH_SHORT).show();
}
});
}

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8

Hello, first of all, I suggest you, to use Backendless v4, because support of 3.X will be limited, from now you can not create new applications with 3.X more details here https://backendless.com/backendless-4-has-been-released-out-of-beta/

here it is an example how to use BackendlessCollection


BackendlessDataQuery dataQuery = new BackendlessDataQuery();
QueryOptions queryOptions = new QueryOptions();
queryOptions.setPageSize( 25 );
queryOptions.setOffset( 50 );
dataQuery.setQueryOptions( queryOptions );
Backendless.Data.of( Person.class ).find( dataQuery, 
                                       new AsyncCallback&lt;BackendlessCollection&lt;Person&gt;>()
  {
    @Override
    public void handleResponse( BackendlessCollection&lt;Person&gt; response )
    {
      // the "response" object is a collection of Person objects.
      // each item in the collection represents an object from the "Person" table 
      
      List&lt;Person&gt; persons = response.getCurrentPage();
      
      for(Person person : persons)
      {
      	System.out.println(person);
      }
    }
 
    @Override
    public void handleFault( BackendlessFault fault )
    {
       // use the getCode(), getMessage() or getDetail() on the fault object
       // to see the details of the error
    }
    });

notice, that BackendlessCollection was removed in Backendless 4, so when you are ready move to Backendless 4 you will need to rewrite your code