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Enriching Data¶

Introduction¶

Enriching data involves integrated the data received into a streaming integration flow with data from other medium such as a data store, another data stream, or an external service to derive an expected result. To understand the different ways in which this is done, follow the sections below.

Enrich data by connecting with a data store¶

This section explains how to enrich the data in a specific stream by joining it with a data store. For this purpose, consider a scenario where you receive sales records generated from multiple locations as events via a system.

Before you begin:

In this scenario, you need to enrich the sales information you receive based on the records in a database table. You can download and install MySQL, and create this table before you carry out the procedure in this subsection.
For detailed instructions to create a database table, expand the following section.

Create Table

Download and install the MySQL Server.
Download the MySQL JDBC driver.
Unzip the downloaded MySQL driver zipped archive, and copy the MySQL JDBC driver JAR (mysql-connector-java-x.x.xx-bin.jar) into the <SI_HOME>/lib directory.
Enter the following command in a terminal/command window, where username is the username you want to use to access the databases.
mysql -u username -p
When prompted, specify the password you are using to access the databases with the username you specified.

Add the following configurations for three database tables under the Data Sources Configuration section of the <SI_HOME>/conf/server/deployment.yaml file.

  - name: UserDataDB
    description: Datasource used for User Data
    jndiConfig:
      name: jdbc/test
      useJndiReference: true
    definition:
      type: RDBMS
      configuration:
        jdbcUrl: 'jdbc:mysql://localhost:3306/UserDataDB?useSSL=false'
        username: root
        password: root
        driverClassName: com.mysql.jdbc.Driver
        maxPoolSize: 50
        idleTimeout: 60000
        connectionTestQuery: SELECT 1
        validationTimeout: 30000
        isAutoCommit: false

To create a database named UserDataDB with a table named UserTable issue the following commands from the terminal:

To create the UserDataDB table:

mysql> create database UserDataDB;
mysql> use UserDataDB;
mysql> source <SP_HOME>/wso2/editor/dbscripts/metrics/mysql.sql;
mysql> grant all on UserDataDB.* TO username@localhost identified by "password";

To create the UserTable table: create table UserTable ( userId LONG, firstname VARCHAR, lastname VARCHAR, )

Start creating a new Siddhi application. You can name it EnrichingTransactionsApp For instructions, see Creating a Siddhi Application.
Define the input stream and the database table that need to be joined as follows.
1. Define the stream as follows. define stream TrasanctionStream (userId long, transactionAmount double, location string);
2. Define the table as follows. define table UserTable (userId long, firstName string, lastName string);
Then define the Siddhi query to join the stream and the table, and handle the result as required.
1. Add the from clause as follows with the join key word to join the table and the stream.
```
from TransactionStream as t join UserTable as u on t.userId == u.userId
```
  Info
  
  Note the following about the from clause: - In this example, the input data is taken from both a stream and a table. You need to assign a unique reference for each of them to allow the query to differentiate between the common attributes. In this example, TransactionStream stream is referred to as t, and the UserTable table is referred to as u. - The join keyword joins the stream and the table together while specifying the unique references. - The condition for the stream and the table to be joined is t.userId == u.userId, which means that for an event to be taken from the TransactionStream for the join, one or more events that have the same value for the userId must exist in the UserTable table and vice versa.
2. To specify how the value for each attribute in the output stream is derived, add a select clause as follows.
```
select t.userId, str:concat( u.firstName, " ", u.lastName) as userName, transactionAmount, location
```
  Info
  
  Note the following in the select statement: - The userId attribute name is common to both the stream and the table. Therefore, you need to specify from where this attribute needs gto be taken. Here, you can also specify u.userId instead of t.userId. - You are specifying the output generated to include an attribute named userName. The value for that is derived by concatenating the values of two attributes in the UserTable table (i.e., firstName and lastName attributes) by applying the str:concat() function. Similarly, you can apply any of the range of Siddhi functions available to further enrich the joined output. For more information, see Siddhi Extensions.
3. To infer an output stream into which the enriched data must be directed, add the insert into clause as follows. insert into EnrichedTrasanctionStream;

The completed Siddhi application is as follows.

@App:name("EnrichingTransactionsApp")


define stream TrasanctionStream (userId long, transactionAmount double, location string);

define table UserTable (userId long, firstName string, lastName string);

from TrasanctionStream as t join UserTable as u on t.userId == u.userId 
select t.userId, str:concat( u.firstName, " ", u.lastName) as userName, transactionAmount, location
insert into EnrichedTrasanctionStream;

Enrich data by connecting with another stream of data¶

This section explains how to enrich the data in a specific stream by joining it with another stream.

To understand how this is done, consider a scenario where you receive information about cash withdrawals and cash deposits at different bank branches from two separate applications. Therefore, this two types of information are captured via two separate streams. To compare the withdrawals with deposits and observe whether enough deposits are being made to manage the withdrawals, you need to join both these streams. To do this, follow the procedure below.

Start creating a new Siddhi application. You can name it BankTransactionsApp For instructions, see Creating a Siddhi Application.
First, define the two input streams via which you are receiving informations about withdrawals and deposits.
1. Define a stream named CashWithdrawalStream to capture information about withdrawals as follows. define stream CashWithdrawalStream(branchID int, amount long);
2. Define a stream named CashDepositsStream to capture information about deposits as follows. define stream CashDepositsStream(branchID string, amount long);
Now let's define an output stream to which the combined information from both the input streams need to be directed after the join.
```
@sink(type='log', prefix='Cash withdrawals that go beyond sustainability threshold:')
define stream CashFlowStream(branchID string, withdrawalAmount long, depositAmount long);
```
Info

A sink annotation is connected to the output stream to log the output events. For more information about adding sinks to publish events, see the Publishing Data guide.
To specify how the join is performed, and how to use the combined information, write a Siddhi query as follows.
1. To perform the join, add the from clause as follows.
```
from CashWithdrawalStream as w
    join CashDepositStream as d
    on w.branchID == d.branchID
```
  Info
  
  Observe the following about the above from clause: - Both the input streams have attributes of the same name. To identify each name, you must specify a reference for each stream. In this example, the reference for the CashWithdrawalStream is w, and the reference for the CashDepositsStream stream is d. - You need to use join as the keyword to join two streams. The join condition is w.branchID == d.branchID where branch IDs are matched. An event in the CashWithdrawalStream stream is directed to the CashFlowStream if there are events with the same branch ID in the CashDepositStream and vice versa.
2. To specify how the value for each attribute is derived, add a select statement as follows.
  
  select w.branchID as branchID, w.amount as withdrawals, d.amount as deposits
  
  Info
  
  The branchID attribute name is common to both input streams. Therefore, you can also specify d.branchID as branchID instead of w.branchId as branchId.
3. To filter only events where total cash withdrawals are greater than 95% of the cash deposits, add a having clause as follows.
  
  having w.amount > d.amount * 0.95
4. To insert the results into the CashFlowStream output stream, add the insert into clause as follows.
  
  insert into CashFlowStream;

The completed Siddhi application is as follows:

@App:name("BankTransactionsApp");

define stream CashWithdrawalStream(branchID int, amount long);

define stream CashDepositsStream(branchID string, amount long);

@sink(type='log', prefix='Cash withdrawals that go beyond sustainability threshold:')
define stream CashFlowStream(branchID string, withdrawalAmount long, depositAmount long);

from CashWithdrawalStream as w
    join CashDepositStream as d
    on w.branchID == d.branchID
select w.branchID as branchID, w.amount as withdrawals, d.amount as deposits
having w.amount > d.amount * 0.95

For the different types of joins you can perform via Siddhi logic, see Siddhi Query Guide - Join

Enrich data by connecting with external services¶

This section explains how to enrich the data in a specific stream by connecting with an external service and adding information received from that service to the existing data.

To understand how this is done, consider an example where you have some credit card numbers, but need to connect with an external service to identify the credit card companies that issued them, and then save that information in a database. To do this, follow the procedure below.

Before you begin:

To save the enriched information in a database table, install and set up MySQL, and create a database. Then create a table in that database named CCInfoTable. For detailed instructions, see the Enrich data by connecting with a data store section.

If you want to try out this guide, you can access the external service used in the example here. This service returns the credit card type when a credit card number is submitted.

Click here for an example

Request Details

POST /ArgoFire/validate.asmx/GetCardType HTTP/1.1 
Host: secure.ftipgw.com 
Content-Type: application/x-www-form-urlencoded 
Content-Length: length 
CardNumber=4111111111111111


- **Response Details**

HTTP/1.1 200 OK 
Content-Type: text/xml; charset=utf-8 
Content-Length: length 

<?xml version="1.0" encoding="utf-8"?> 
<string xmlns="http://localhost/SmartPayments/">VISA>

Start creating a new Siddhi application. You can name it CCTypeIdentificationApp For instructions, see Creating a Siddhi Application.
Define the input stream from which the input data (i.e., the credit card no in this example) must be taken.

define stream CreditCardStream (creditCardNo string);

To publish the input data to the external application, connect a sink to the stream you created as shown below. For more information about publishing information, see the Publishing Data guide.

Info

Note the following about the above sink definition: - It is assumed that the external application receives requests in HTTP. Therefore, the sink type is http-request. - The publisher.url parameter specifies the URL to which the outgoing events need to be published via HTTP. - For more information about the HTTP transport, see Siddhi Extensions - Siddhi IO HTTP.
To capture the response of the external application once it returns the credit card type, define a stream as follows. For more information about consuming data, see the Consuming Data guide.

define stream EnrichedCreditCardStream (creditCardNo string,creditCardType string);
Assuming that the external application sends its output via the HTTP transport, connect a source of the httptype to the EnrichedCreditCardStream stream as follows. For more information about consuming events published to SI, see the Consuming Data guide.
```
@source(type='http-response' ,sink.id='cardTypeSink',    
@map(type='xml', namespaces = "xmlns=http://localhost/SmartPayments/",    
@attributes(creditCardNo = 'trp:creditCardNo',creditCardType = ".")))        
define stream EnrichedCreditCardInfoStream (creditCardNo string,creditCardType string);
```
Info

It is assumed that the external application sends requests in HTTP. Therefore, the source type is http-request. For more information about the HTTP transport, see Siddhi Extensions - Siddhi IO HTTP.
To save the response of the external application, define a table named CCInfoTable.

define table CCInfoTable (cardNo long, cardType string);
To save the data enriched by integrating the information received from the external service, add a Siddhi query as follows.
```
from EnrichedCreditCardInfoStream
select *
update or insert into CCInfoTable;
```
The above query selects all the attributes in the EnrichedCreditCardInfoStream and inserts them into the CCInfoTable table. If a specific record already exists,the query updates it by replacing the attribute values with the latest values taken from the EnrichedCreditCardInfoStream.

The completed Siddhi application is as follows:

@App:name("CCTypeIdentificationApp")

@sink(type='http-request',publisher.url='https://secure.ftipgw.com/ArgoFire/validate.asmx/GetCardType',method='POST', headers="'Content-Type:application/x-www-form-urlencoded'",
sink.id="cardTypeSink",
@map(type='keyvalue', @payload(CardNumber='{{creditCardNo}}')))
define stream CreditCardStream (creditCardNo string);

@source(type='http-response' ,sink.id='cardTypeSink',    
@map(type='xml', namespaces = "xmlns=http://localhost/SmartPayments/",    
@attributes(creditCardNo = 'trp:creditCardNo',creditCardType = ".")))        
define stream EnrichedCreditCardInfoStream (creditCardNo string,creditCardType string);

from EnrichedCreditCardInfoStream
select *
update or insert into CCInfoTable;

Enrich data using built-in extensions¶

The following is a list of Siddhi extensions with which you can enrich data.

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