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There are several approaches to iterating, each having their particular usage: using the foundset iterator, changing the selected index of the foundset, accessing a record object, accessing data provider values as an array.

Using the founset iterator is mostly While the last three iterating options are more intuitive, and also vary with regards to performance and usage, the foundset iterator is the most recommended to be used since

Changing the Selected Index

Perhaps the most intuitive approach is to programmatically change the foundset's selected index property. 

Example: The example below iterates over the entire foundset using a for loop.

for(var i = 1; i <= foundset.getSize(); i++){
	foundset.setSelectedIndex(i);
	// operate on the selected record
}

See also the JSFoundset's setSelectedIndex method.

Accessing a Record Object

While setting the selected index of the foundset is sometimes necessary, it also contains some overhead and therefore is not always the most efficient way to iterate over a foundset. However, one can iterate in a similar manner, access a record object without changing the selected index of a foundset by using the getRecord method of the foundset.

Example This example iterates over the foundset, but does not affect the selected index. The performance will be better than the previous example, and will not have any side effects in the UI if the foundset is bound to a form.

for(var i = 1; i <= foundset.getSize(); i++){
	var rec = foundset.getRecord(i);	// does not affect the selected index
}

See also the JSFoundset's getRecord method.

Accessing Data Provider Values As an Array

Sometimes the purpose of iterating over a foundset is to access all the values for a particular data provider. The most efficient way to do this is to obtain an array of values for the foundset's data provider using the getFoundSetDataProviderAsArray method of the databaseManager API.

Example This example shows how to access all the values in a foundset for a single data provider. Iterating over a simple array offers better performance over normal foundset iteration.

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it is the only option that ensures iterating over all the records of the foundset, not missing any of them due to the multiple clients performing changes on the same foundset at the same time.

It is also possible to use JSFoundsetUpdater API to iterate over and update a foundset.

Using the Foundset Iterator

Sometimes there is more than one user working on the same foundset, possibly inserting or deleting records. When iterating on a foundset, it needs to be ensured that the loop neither skips nor processes twice any record due to the foundset modifications occurred from other clients. Thus, in such cases, a secure iterator is needed to perform the iteration on the foundset.

The forEach method does exactly that, iterating over all the records of a foundset and calling the callback method given as parameter for each one of them.

Example This is an example of how to use the forEach method for iterating over a foundset.

foundset.loadAllRecords();
foundset.forEach(
			/**
			 * @param {JSRecord} record
			 * @param recordIndex
			 * @param {JSFoundset} fs 
			 */
			function(record, recordIndex, fs) {
				application.output("record processed: " + record + ", record index: " + recordIndex);
			}
		);

See also the JSFoundset's forEach method.

Changing the Selected Index

Perhaps the most intuitive approach is to programmatically change the foundset's selected index property. 

Example: The example below iterates over the entire foundset using a for loop.

for(var i = 1; i <= foundset.getSize(); i++){
	foundset.setSelectedIndex(i);
	// operate on the selected record
}

See also the JSFoundset's getFoundSetDataProviderAsArray setSelectedIndex method.

Using the Foundset Iterator

Sometimes there is more than one user working on the same foundset, possibly inserting or deleting records. When iterating on a foundset, it needs to be ensured that the loop neither skips nor processes twice any record due to the foundset modifications occurred from other clients. Thus, in such cases, a secure iterator is needed to perform the iteration on the foundset.

The forEach method does exactly that, iterating over all the records of a foundset and calling the callback method given as parameter for each one of them.

Example This is an example of how to use the forEach method for iterating over a foundset.

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Accessing a Record Object

While setting the selected index of the foundset is sometimes necessary, it also contains some overhead and therefore is not always the most efficient way to iterate over a foundset. However, one can iterate in a similar manner, access a record object without changing the selected index of a foundset by using the getRecord method of the foundset.

Example This example iterates over the foundset, but does not affect the selected index. The performance will be better than the previous example, and will not have any side effects in the UI if the foundset is bound to a form.

for(var i = 1; i <= foundset.getSize(); i++){
	var rec = foundset.getRecord(i);	// does not affect the selected index
}

See also the JSFoundset's getRecord method.

Accessing Data Provider Values As an Array

Sometimes the purpose of iterating over a foundset is to access all the values for a particular data provider. The most efficient way to do this is to obtain an array of values for the foundset's data provider using the getFoundSetDataProviderAsArray method of the databaseManager API.

Example This example shows how to access all the values in a foundset for a single data provider. Iterating over a simple array offers better performance over normal foundset iteration.

var ids = databaseManager.getFoundSetDataProviderAsArray(foundset,'order_id');
for(i in ids){
    var id = ids[i];
}

See also the JSFoundset's forEach getFoundSetDataProviderAsArray method.

Related Foundsets

Foundsets are often constrained or filtered by a Relation. In this situation, the foundset is said to be a Related Foundset and its default SQL query will include in its Where Clause, the parameters by which to constrain the foundset.

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