Best way for displaying total Pages for a datasource in Appmaker

问题

I have a Google drive table data source which stores list of open positions. Now in the data source I've set "Query per size" field to 10 so that I can get 10 records per page. I've added a Pager as well to show pagination.

My query is I want to display like "Page 1 of X" to my end users and this X will vary based on certain search filters. What will the best way to achieve this in Appmaker?

I've tried counting total records in a data source as per below code but every time updating that with the search criteria and recounting it is not a proper solution.

//Server side
    var newQuery = app.models.Company.newQuery();
    var records = newQuery.run();
    var totalCount =0;
    for(var i=0;i<records.length;i++)
    {
       totalCount=totalCount+1;
    }
    return totalCount;

回答1:

In case you don't have any filters in your table your server code can be as simple as

// Server script
function getPagesCount(pageSize) {
  var recordsCount = app.models.MyModel.newQuery().run().length;
  var pagesCount = Math.ceil(recordsCount / pageSize);

  return pagesCount;
}

As an alternative you can consider creating Calculated Model with a single field PagesCount.

In case you have some filters associated with the table then you'll need to run the query for the pages number with exact same filters.

Most likely the entire setup will not work effectively with Drive Tables since there is no way to query records number without querying records themselves. With Cloud SQL data backend one can create Calculated SQL Model with lightweight native SQL query (here :PageSize is query parameter which should be equal to the query.limit of the actual datasource):

SELECT
  Ceil(COUNT(1) / :PageSize) AS RecordsNumber
FROM
  TableName
WHERE
  ...

回答2:

I've achieved this using Calculated Model as suggested by Pavel.

Steps :

Create a calculated data source with one field count.
In that data source add one parameter searchQuery. This will contain users filter going forward. Currently I have only one search query in which user can search many things. So I've added one parameter only.
In this data source add following server script.

Code:

// Server script
function getTotalRecords(query) {
  var receivedQuery = query.parameters.searchQuery;
  // console.log('Received query:' + query.parameters.searchQuery);

  var records = app.models.Company.newQuery();
  records.parameters.SearchText = query.parameters.searchQuery;

  if(receivedQuery !== null) {
    records.where = '(Name contains? :SearchText or InternalId contains? ' +
      ':SearchText or LocationList contains? :SearchText )';
  }

  var recordsCount = records.run().length;
  var calculatedModelRecords = []; 
  var draftRecord = app.models.RecordCount.newRecord();
  draftRecord.count = ''+recordsCount;
  calculatedModelRecords.push(draftRecord);

  return calculatedModelRecords;
}

On the Appmaker page bind a label with this data source.
On search query/your filter applied event add following code which Reload this data source and assign value to Parameter.

// Client script
function updateRecordCount(newValue) {
  var ds = app.datasources.RecordCount;
  ds.query.parameters.searchQuery = newValue;
  ds.unload();
  ds.load();
}

来源：https://stackoverflow.com/questions/50582355/best-way-for-displaying-total-pages-for-a-datasource-in-appmaker

标签

google-app-maker