Here's a scenario where you may not think of using DAX_DevHook_OnQuery as a solution: You need to send custom variables to the back-end, perform some operations in the database and send custom variables back to the front end. However, DAX_DevHook_OnQuery can prove very useful in this kind of situation.

All you need to do is setup your JavaScript in the front-end to perform a "query" on a table (preferably one not used for queries) in the back-end and send some custom variables. In the back-end using DAX_DevHook_OnQuery detect the table, perform the operation and send some custom variables back to the front-end.

Front-End Code:

// Not a real query, just to receive values from BE var getValues; // To get Client information from BE var client_name; var client_status; var client_balance; // Create a new query in your dax_loginSuccess function: function dax_loginSuccess() { getValues= new dax_query('Preferences'); // new query for table Preferences } // Create a function to initiate the query and send the custom variables: function FEtoBE(){ // pass variables to BE getValues.newQuery(); getValues.clearCustomValues(); getValues.addCustomValue('BE_CientID', BE_CientID ); getValues.runQuery(); } // Create a function to retrieve the custom variables: function BEtoFE() { // Retrieve variables from BE BEInfo = dax_bridge.getCustomLoginValuesFrom4D(); client_name = BEInfo[0].value; client_status = BEInfo[1].value; client_balance = BEInfo[2].value; }

Back-End Code:

The idea here is to detect the query using DAX_DevHook_OnQuery, get the custom variables, perform any operation on the database and send custom variables back.

`DAX_DevHook_OnQuery   `Passed:   `$1 LONGINT-Table number of the table that gets the Selection   `$2 POINTER-Pointer to a Longint Array of Table Numbers   `$3 POINTER-Pointer to a Longint Array of Field Numbers   `$4 POINTER-Pointer to a Text Array of Values to Query For   `$5 POINTER-Pointer to a Text Array of Query Comparators   `$6 POINTER-Pointer to a Text Array of Query Line Links   `$7 BOOLEAN-Flag: Query in Current Selection†00:00:00†   `Returned:   `$0 BOOLEAN-Flag: Developer Performed the Query   `   `By default the parameters are assigned to local variables as follows: $selectionNumber_l:=$1 $tableNumbers_p:=$2 $fieldNumbers_p:=$3 $queryValues_p:=$4 $queryComparators_p:=$5 $queryLineLinks_p:=$6 $queryInSelection_b:=$7 C_TEXT($clientID_value_t) ARRAY TEXT(customname_at;3) ARRAY TEXT(customvalue_at;3) $queryDone_b:=True   ` get the name of the table from the passed ID $tableName_t:=Dax_Dev_Struct_GetNameFromID ($selectionNumber_l) Case of : ($tableName_t="Preferences") $clientID_value_t:=DAX_Dev_GetWebVar ("BE_ClientID")   `Query the Clients table READ ONLY([Clients]) QUERY([Clients];[Clients]ClientiD=Num(clientID_value_t)) customname_at{1}:="client_name" customname_at{2}:="client_status" customname_at{3}:="client_balance" Case of : (Records in selection([Clients])=1) customvalue_at{1}:=[Clients]Client_Name customvalue_at{2}:=[Clients]Client_Status customvalue_at{3}:=String([Clients]Client_Balance) else customvalue_at{1}:="Not found" customvalue_at{2}:="" customvalue_at{3}:="" End case   `Send Custom Variable back to Front-End DAX_Dev_SetCustomVariables (->customname_at;->customvalue_at) End case $0:=$queryDone_b