WBDSERVICES

WSDL is a XML based language used to create service descriptions. we have two types of wsdl.

Two types of wsdl
1.Enterprise WSDL: A strongly typed wsdl for customers who want to build an integration with their Salesforce.com organization only
strongly typed means: here we can work with objects and fields with specific data types like int and string.

2.Partner WSDL : A loosely typed wsdl for customers, partners who are building client applications for multiple organisations.
loosely typed
 means: here we can work with objects, fields and vlaues with any data type.

Generally we save all the WSDL files with .wsdl extension.

To generate wsdl files ,      setup-->develop-->API
Generation of wsdl from apex,     setup-->develop-->apex classes-->generate from wsdl


Q: Differences between xml and wsdl?
XML (eXtensible Markup Language) is a set of rules for encoding documents.
WSDL is a XML based language used to create service descriptions

Q: how many ways we can generate session id in salesforce using soap
We can use login() method

syntax:
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loginresult = connection.login(string username, string password)

Q: What is the difference between single/two/three steps authentication?
Single step authentication is with Username and password.
Two step authentication is with Username , password & a time-based token generated from an authenticator app when they log into Salesforce.

SOAP(Simple Object Access Protocal)
WSDL(Web Service Description Language)
XML(Extensible Markup Language)
SOA(Service Oriented Architecture)
REST(Representational State Transfer)

Purpose:
---------
SOAP API and REST API both are commonly used to expose our data from force.com platform to other platforms(JAVA ,.NET ,etc)
--> SOAP is a XML based messaging protocal used by webservices.
--> SOAP relies on XML to provide messaging services.
     . The purpose of using XML in SOAP is that it is used to make requests and receive responses in SOAP.
--> One of the best features of SOAP is "built-in error handling"
Ex: Let us assume that If there’s a problem with your request, then what happens the response contains error information in order to fix the problem we use this one.


-->Generally REST provides a lighter weight alternative.
-->REST relies on a simple URL in many cases to make request.
-->REST ful web services communicate by HTTP do not require XML messages or WSDL service API definitions.
-->REST can return XML, Plain text, JSON(javascript object notation), HTML etc.

SOA:
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-->Lets say we have a software called "service consumer" it wants to talk to another software lets called that "service provider" , cosumer software is going to send a service request or message to the provider software and the provider software is going to reply back with service response. When the request is received by service provider software it is processed by service .
-->service: it is a well defined funtion that does not depend on the state of other services.
-->consumer software needs to know that how to call the service for example what parameters , arguments the service is expecting

SOA deff:
-----------
SOA is a solution for making two software commuicate to each other.
Web services is an implementation of SOA.

-->The webservice which is developed with any technology like java,php,.net etc that is available to us in the form of WSDL.


"Each key is a property of JSON object"
ex:  var obj1={user(key):"sathya", age(key):23, country(key):"india" etc....};