QueryEach
Iterates over query rows and passes each row per iteration to a callback function.
This function is used to perform an action for each row in the query. It does not return a value, but rather allows you to perform side effects such as printing or modifying data.
Parallel Execution
If the parallel argument is set to true, and no max_threads are sent, the filter will be executed in parallel using a ForkJoinPool with parallel streams.
If max_threads is specified, it will create a new ForkJoinPool with the specified number of threads to run the filter in parallel, and destroy it after the operation is complete.
Please note that this may not be the most efficient way to iterate, as it will create a new ForkJoinPool for each invocation of the BIF. You may want to consider using a shared ForkJoinPool for better performance.
Method Signature
QueryEach(query=[query], callback=[function:Consumer], parallel=[boolean], maxThreads=[integer], ordered=[boolean])Arguments
query
query
true
The query to iterate over
callback
function:Consumer
true
The function to invoke for each item. The function will be passed 3 arguments: the row, the currentRow, the query. You can alternatively pass a Java Consumer which will only receive the 1st arg.
parallel
boolean
false
Whether to run the filter in parallel. Defaults to false. If true, the filter will be run in parallel using a ForkJoinPool.
false
maxThreads
integer
false
The maximum number of threads to use when running the filter in parallel. If not passed it will use the default number of threads for the ForkJoinPool. If parallel is false, this argument is ignored.
ordered
boolean
false
false
Examples
Iterate over query rows instead of bx:loop()
<bx:script>
news = queryNew( "id,title", "integer,varchar", [
{
"id" : 1,
"title" : "Dewey defeats Truman"
},
{
"id" : 2,
"title" : "Man walks on Moon"
}
] );
function newsRow( Any row ) {
writeOutput( "<tr>" );
writeOutput( "<td>#row.ID#</td>" );
writeOutput( "<td>#row.TITLE#</td>" );
writeOutput( "</tr>" );
}
</bx:script>
<table>
<bx:script>
queryEach( news, newsRow );
</bx:script>
</table>Result: 1 Dewey defeats Truman 2 Man walks on Moon
Iterate over query rows instead of bx:loop()
<bx:script>
news = queryNew( "id,title", "integer,varchar", [
{
"id" : 1,
"title" : "Dewey defeats Truman"
},
{
"id" : 2,
"title" : "Man walks on Moon"
}
] );
function newsRow( Any row ) {
writeOutput( "<tr>" );
writeOutput( "<td>#row.ID#</td>" );
writeOutput( "<td>#row.TITLE#</td>" );
writeOutput( "</tr>" );
}
</bx:script>
<table>
<bx:output>#queryEach( news, newsRow )#</bx:output>
</table>Result: 1 Dewey defeats Truman 2 Man walks on Moon
Additional Examples
people = QueryNew( "name,dob,age", "varchar,date,int", [
[
"Susi",
CreateDate( 1970, 1, 1 ),
0
],
[
"Urs",
CreateDate( 1995, 1, 1 ),
0
],
[
"Fred",
CreateDate( 1960, 1, 1 ),
0
],
[
"Jim",
CreateDate( 1988, 1, 1 ),
0
]
] );
Dump( var=people, label="people - original query" );
/* Output:
*
* | name | dob | age |
* ------------------------------------
* | Susi | 1970-01-01 00:00:00 | 0 |
* | Urs | 1995-01-01 00:00:00 | 0 |
* | Fred | 1960-01-01 00:00:00 | 0 |
* | Jim | 1988-01-01 00:00:00 | 0 |
*
*/
people.each( ( Any row, Any rowNumber, Any recordset ) => {
recordset.AGE[ rowNumber ] = DateDiff( "yyyy", row.DOB, Now() );
} );
Dump( var=people, label="people - with calculated age" );
/* Output:
*
* | name | dob | age |
* ------------------------------------
* | Susi | 1970-01-01 00:00:00 | 45 |
* | Urs | 1995-01-01 00:00:00 | 20 |
* | Fred | 1960-01-01 00:00:00 | 55 |
* | Jim | 1988-01-01 00:00:00 | 27 |
*
*/Related
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