Some Basic Differences:

Question: What is the difference between SOQL and SOSL in Salesforce?

Answer: 

SOQL	SOSL
It’s a Salesforce Object Query Language.	It’s a Salesforce Object Search Language.
Using SOQL we can search only on one object at a time.	Using SOSL we can search on many objects at a time.
We can query on all fields of any data type.	We can query only on fields whose data type is text, phone and Email.
We can use SOQL in Triggers and Classes.	We can use SOSL in Classes but not in Triggers.

Question:  What Is the difference between Custom Settings and Custom Object?

 Answer: 

Question: What is a difference between data loader and import wizard in salesforce?

 Answer:  

Question: what is the difference between data import wizard pilot and import wizard?

 Answer:  

 

Question: What is the difference between actionFunction and actionSupport tags?

 Answer: 

	ActionSupport	ActionFunction
1)	Directly call action method without JavaScript.	Call action method from JavaScript with AJAX.
2)	It can be used to call action method on  single event.	It can be used to call action method on different event.
3)	It cannot be called from JavaScript function. It only invoke controller action methods from other Visualforce components.	It defines a new JavaScript function which can then be called from within a block of JavaScript code.

Question: How to Export data using data loader and what is the difference between Export and Export all

Export:
So for we seen insert,update and upsert. There are the data import to salesforce. Some times we need data from saleforce. So data Export is needed to get data.
Now follow the step by step how to do this.

1. Click on the data loader icon on the desktop.

 

2. Then click on Export.Select the object to export and it's automatically selects extract.csv file otherwise you can select a .csv file to save data.

3. Then click on next. Here write simple SOQL query to select the data.
Choose the query fields below is the fields to export and create the where clauses to your query below is the SOQL query to filter the data. We simply select it will generate the SOQL query below editor.

4. Then click finish and it's done.

Export All:
We know using data loader to export all the data, but what is this export all data. Export only exports the records from object. But Export all is export data from Object and Recycle bin also. This is a major difference between exports and export all operations.

Follow the same steps followed by export. But first selection of operation is Export All button OK.

Question: What is upsert and what is the difference between update and upsert?

Upsert: Using data loader insert operation to insert and update operation to update records. But what is this upsert. Upsert mean combination of Update and Insert. I know you have question mark in your face. Some time update old records and insert new records. Now Upsert is come in to the picture to full fill the both insert and update operations. Existing records will be updated and new records will be inserted.
The following steps explain Upsert records in to salesforce using apex data loader.
1. Open the data loader, Select the Upsert operation.

 

2. Select the Object to upsert and select the .csv file also.

 

3. Then map the fields properly.

 

4. Then Click on Next button. It will ask conformation. Click on OK. 

 

5. Operation success zero errors and success. That's it.

Question: How To Switch ON The Development Mode in Salesforce?

Enable Development Mode:

 
Name--> My Settings --> Personal--> Advanced User 

Details--> Edit --> Enable Development Mode Check box.

 

Then Click On Save. You Turned ON the Development mode. 

Question: What is difference between Master-Details and Lookup Relationship? 

Answer:

Master-Details Relationship	Lookup Relationship
Child records should be associated to parent.	Optional, child records need not be associated to a parent.
Cascade record deletion.	No Cascade record deletion.
Standard objects cannot be a detail object. (Child object)	No such restrictions.
The Master-Details Relationship, field is required on the page layout of the detail object.	Lookup field on child not necessarily required.
Roll-up summary fields can be created on the parent object.	Cannot be establishing here.
Detail record inherits the sharing and security setting of its master record.	No effect on security.

Thanks.....