Insert (audit) changes for the current entity (table or view).
Call an external resource.
For example, you can have your event rule determine the lat/long coordinates to be used in a Google map for product delivery. You do this using an event rule that passes a customer's address to a resource which in turn calls Google Geocode.
Send email.
Update a calendar system.
Post a message on a queue.
Call a push notification engine.

Event.
 Fires after it completes the row logic. The row data reflects derivation results.
You can change the row within the code of an event rule, but you must ensure that required logic is executed using the 
logicContext.save()
 method.
Early event.
 Fires before it executes your logic. 
CA Live API Creator
 does not subjects the row data to formula rules and other derivation rules. You can change the rows and 
CA Live API Creator
 subjects the changes to validations, other chained logic, and saves the changes.
Commit event.
 Fires after it completes row logic for all the rows in the transaction. The rows reflect logic processing. You cannot change the rows.
Pre-Insert event.
 Fires before it sends the row to the database on insert. You can have 
CA Live API Creator
 generate an alphanumeric primary key using a pre-insert event rule that computes the keys. You can also have 
CA Live API Creator
 compute a non-nullable attribute before inserting a row into the table using a pre-insert event rule.

About resource events, see Manage Resource Events.
About the "think spreadsheet" concept, see Logic Patterns.

Define Order event MaintainCount as
if (logicContext.initialVerb == 'INSERT' && row.isPaid == false) { // row is the order
    customer = row.customer; // parent accessor
    customer.balance += row.amountTotal;
    logicContext.update(customer);
}

Delete order: Decrement the count only if the order 
isPaid
.
Change 
Order.isPaid
: Watch for such a change, and if you detect it, adjust the sum by amountTotal.
Change 
Order.amountTotal
: Watch for such a change, and if you detect it, adjust the sum by the difference.
Reassign order: Often overlooked, reduce the previous customers' 
balance
, increase the new one, only if the order 
isPaid
.

Cell A =
  Sum(ColumnB)

Customer.balance = 
  sum(orders.amountTotal where paid = false)

In the Create section, click 
Rules
.
If your API does not have existing rules, the Welcome to Rules page appears. If your API has existing rules, they are listed on the 
By entity
 tab by default.
Click 
Create a Rule
.
Do the following:
Specify when the event is fired by selecting one of the following event rule types:
Event
 
Early Event
 
Commit Event
 
Pre-Insert Event
 
If you want to change primary keys within an event, select 
Early Event
, 
Commit Event
, or 
Pre-Insert Event
.
Select the entity to which the rule applies.
Click 
Create Rule
.
Define the parameters of the rule, and then click 
Activate and Close
:
Title
 
The title for the event rule. The title for rules does not affect logic processing. To apply a default value, leave this field blank.
Required:
 No
Entity
 
The name of the entity that 
CA Live API Creator
 is acting upon.
Topics
 
The topic that you want to associate to this rule.
For more information about topics, see Manage Topics.
Code
 
The code for your event rule. You can access and insert JavaScript code examples into the code editor.
For more information about the code examples that are available for event rules, see JavaScript Code Examples.
You can have 
CA Live API Creator
 return an object and assign it to an entity resource attribute. This object represents the current date, time, or timestamp on the database server at the instant the resulting SQL is executed on the database server. You can do this by way of the 
SysUtility
 JavaScript object's 
databaseNowDeferred()
 method or the 
sqlSnippetDeferred()
 method.
For more information about these methods, see The SysUtility Object.
 
Example 1:
 A typical example is an auditing event. This example uses of the current/old row in making your logic conditional:
if (row.amount_total != oldRow.amount_total) 
  SysLogic.insertChildFrom("purchaseorder_audit", logicContext);
Example 2:
 The following example is an event rule that uses the current/old row to verify the condition of the product and do the following:
Create a JSON string, per the format of the 
ComplianceReporting
 resource, using the 
SysUtility.getResource()
 method.
Post or send the JSON string to a message queue (this is not shown in the code).
 
if (row.name == "Dynamite" && row.total_quantity_ordered != oldRow.total_quantity_ordered) {
    log.debug("***controlled substance - notify authorities");
    var json = JSON.parse(req.json); // convert req's JSON string to JSON objects
    var custName = json.customer; // get the name from the request
    var options = { sysfilter: "equal(name:'" + custName + "')" };
    var custAccount = SysUtility.getResource("ComplianceReporting", options); // get resource JSON
    log.debug("***sending compliance message" + JSON.stringify(custAccount[0]));
}
This code is from the 
Controlled Substance Reporting
 event rule in the 
Sample
 API.
Active
 
Select to activate the rule.
Default:
 Cleared
The API must be complete.
Asynchronous
 
Select this checkbox to have 
CA Live API Creator
 execute the event rule asynchronously, independent of the current transaction. The execution of the event does not affect the current transaction. Running your request event asynchronously can be helpful for processes that might take a long time, such as making an external call or sending an email.
Name
 
The name of the event rule. Leave this field blank to accept the default.

row
 and 
oldRow
 . The current row (the 
row
 object) reflects client changes from JSON, and all logic processing. The previous row (the 
oldRow
 object) reflects the row before the transaction started. This object is from the database read. It has the prior values of the object being updated, so you can detect changes. Event rules can also access the values of any parent rows.
For more information about row logic, see Logic Execution.
Logic context.
 You can read/write other rows using the system methods that are included with the 
logicContext
 object.
For more information about this object, see The logicContext Object.
Logic services.
 You can use the system methods that are included with the 
SysLogic
 object in validation rules, formula rules, and event rules.
For more information:
About this object, see The SysLogic Object.
About event context, see the "Event Context" section.