Everyone has an idea but matters only how we innovate and takes further.
Tuesday, October 16, 2012
Friday, October 12, 2012
Difference between JOIN and UNION
JOIN
JOIN is used to display data from more than two tables.
SELECT FIRST_NAME ,LAST_NAME,JOB_ID FROM TABLE1 T1 JOIN TABLE2 T2 ON
(T1.JOB_ID=T2.JOB_ID);
NOTES: To join n tables together, we need a minimum of n-1 join conditions.
UNION
UNION is used to display combined data from two tables into a single result set.
SELECT FIRST_NAME ,LAST_NAME,JOB_ID FROM TABLE1
UNION
SELECT FIRST_NAME ,LAST_NAME,JOB_ID FROM TABLE2
NOTES: The number of columns and order must match in all tables.
JOIN is used to display data from more than two tables.
SELECT FIRST_NAME ,LAST_NAME,JOB_ID FROM TABLE1 T1 JOIN TABLE2 T2 ON
(T1.JOB_ID=T2.JOB_ID);
NOTES: To join n tables together, we need a minimum of n-1 join conditions.
UNION
UNION is used to display combined data from two tables into a single result set.
SELECT FIRST_NAME ,LAST_NAME,JOB_ID FROM TABLE1
UNION
SELECT FIRST_NAME ,LAST_NAME,JOB_ID FROM TABLE2
NOTES: The number of columns and order must match in all tables.
Thursday, October 11, 2012
Difference between ORDER BY and GROUP BY
ORDER BY
ORDER BY is used to sort the rows.It affects only the order of result set.
SELECT FIRST_NAME,LAST_NAME,JOB_ID,DEPARTMENT_ID FROM EMPLOYEE
ORDER BY JOB_ID
NOTE:If we are using ORDER BY clause,it must be last clause of the SQL statement.
GROUP BY
GROUP BY is used to divide the rows into group in a table. GROUP BY specifies how the rows should be grouped.
SELECT DEP_ID,AVG(SAL) FROM EMPLOYEE
GROUP BY DEP_ID
NOTE:Rows are sorted by ascending order of the columns included in the GROUP BY clause by default.
ORDER BY is used to sort the rows.It affects only the order of result set.
SELECT FIRST_NAME,LAST_NAME,JOB_ID,DEPARTMENT_ID FROM EMPLOYEE
ORDER BY JOB_ID
NOTE:If we are using ORDER BY clause,it must be last clause of the SQL statement.
GROUP BY
GROUP BY is used to divide the rows into group in a table. GROUP BY specifies how the rows should be grouped.
SELECT DEP_ID,AVG(SAL) FROM EMPLOYEE
GROUP BY DEP_ID
NOTE:Rows are sorted by ascending order of the columns included in the GROUP BY clause by default.
Wednesday, October 10, 2012
Difference between BETWEEN and IN
BETWEEN
BETWEEN is used to display rows based on a range of values.
SELECT FIRST_NAME, SALARY FROM EMPLOYEE
WHERE SALARY BETWEEN 4000 and 10000;
NOTE: Values specified with the BETWEEN condition are inclusive. We have to specify the lower limit first.
IN
IN is used to test for values in a list
SELECT FIRST_NAME, SALARY, EMP_ID FROM EMPLOYEE
WHERE EMP_ID IN (150,250,300);
NOTE: THE IN condition can be used with any data type.
BETWEEN is used to display rows based on a range of values.
SELECT FIRST_NAME, SALARY FROM EMPLOYEE
WHERE SALARY BETWEEN 4000 and 10000;
NOTE: Values specified with the BETWEEN condition are inclusive. We have to specify the lower limit first.
IN
IN is used to test for values in a list
SELECT FIRST_NAME, SALARY, EMP_ID FROM EMPLOYEE
WHERE EMP_ID IN (150,250,300);
NOTE: THE IN condition can be used with any data type.
Difference between DELETE,DROP and TRUNCATE
DELETE
DELETE is used to remove exiting rows from a table.
DELETE FROM TableName
WHERE condition;
If we omit the WHERE clause all rows in the table are deleted otherwise specific rows are deleted based on the condition. After performing a DELETE operation we need to COMMIT or ROLLBACK the transaction to make the change permanent or to undo it.
NOTE: All DELETE triggers on the table will fire.
DROP
DROP is used to delete the definition of oracle table.When we drop a table,the database loses all the data in the table and all the indexes associates with it.
DROP TABLE TableName
After dropping table any views and synonmys are still remained there but are invalid.
TRUNCATE
TRUNCATE is used to remove all rows from a table and release the storage space used by the table.
TRUNCATE TABLE TableName
NOTE:DROP and TRUNCATE are DDL but DELETE is DML.So when we use TRUNCATE we cannot roll back row removed and even no triggers will be fired.
DELETE is used to remove exiting rows from a table.
DELETE FROM TableName
WHERE condition;
If we omit the WHERE clause all rows in the table are deleted otherwise specific rows are deleted based on the condition. After performing a DELETE operation we need to COMMIT or ROLLBACK the transaction to make the change permanent or to undo it.
NOTE: All DELETE triggers on the table will fire.
DROP
DROP is used to delete the definition of oracle table.When we drop a table,the database loses all the data in the table and all the indexes associates with it.
DROP TABLE TableName
After dropping table any views and synonmys are still remained there but are invalid.
TRUNCATE
TRUNCATE is used to remove all rows from a table and release the storage space used by the table.
TRUNCATE TABLE TableName
NOTE:DROP and TRUNCATE are DDL but DELETE is DML.So when we use TRUNCATE we cannot roll back row removed and even no triggers will be fired.
Tuesday, October 9, 2012
Difference between .exe file and .dll file
In programming environment both .exe and .dll are common.After completion of coding part we usually export it to either .exe or .dll.The basic differences between these two are
1. .exe file is executable file where as .dll is non-executable file.
2..exe file is used to launch application whereas .dll file is dynamic link library which commonly contains functions and procedures that can be used by other programs and is loaded into an application.
3. .exe file runs on its own but .dll can not run on its own and linked or referened to the exe file at run time.
4. one application one .exe file but one application many .dll file.
5..exe file can not be shared with other application but .dll file can be shared with other application.
6..exe file will have main function whereas .dll doesn't have main function.
7.There is only one entry point for .exe file but .dll are having many entry point
8..exe file cannot be reused whereas .dll can be reused.
1. .exe file is executable file where as .dll is non-executable file.
2..exe file is used to launch application whereas .dll file is dynamic link library which commonly contains functions and procedures that can be used by other programs and is loaded into an application.
3. .exe file runs on its own but .dll can not run on its own and linked or referened to the exe file at run time.
4. one application one .exe file but one application many .dll file.
5..exe file can not be shared with other application but .dll file can be shared with other application.
6..exe file will have main function whereas .dll doesn't have main function.
7.There is only one entry point for .exe file but .dll are having many entry point
8..exe file cannot be reused whereas .dll can be reused.
Thursday, September 20, 2012
Monday, September 17, 2012
Introduction to .NET Framework
.Net Architecture
Over last few years there are so many things that have came into picture in the Microsoft .Net environment that help and support developer more and more. It has introduces many concepts, technology and design terms to extends its capabilities and potential aptitude. Microsoft .Net technology has been one of the most excellent boons for developers that provide rapid application development in true aspect.
Microsoft .NET technology has a great future ahead in all spheres ranging from Desktop Applications, Client Server Applications, Distributed Applications, Enterprise Applications, Web Applications, e-commerce store fronts and the most important Mobile Applications.
Architecture
If someone asks that what are the benefits of .Net to the end users and someone says that common language runtime, ASP.NET, WPF, WCF, LINQ, Parallel LINQ, XML integration, Garbage Collection, and so on. Is it an appropriate to say? Obviously no, it all helps to developer not to end users. The benefit of .Net is to users is the new generation of software that .NET introduces: software that runs anywhere, at anytime, on any platform, and from devices large and small.
The .NET Framework is a software framework. It includes a large library and provides language interoperability (each language can use code written in other languages) across several programming languages. Programs written for the .NET Framework execute in a software environment (as contrasted to hardware environment), known as the Common Language Runtime (CLR), an application virtual machine that provides important services such as security, memory management, and exception handling. The class library and the CLR together constitute the .NET Framework.
The .NET Framework's Base Class Library provides user interface, data access, database connectivity, cryptography, web application development, numeric algorithms, and network communications. The Common Language Runtime (CLR) serves as the execution engine of the .NET Framework. All .NET programs execute under the supervision of the CLR, guaranteeing certain properties and behaviors in the areas of memory management, security, and exception handling.
Common Language Specification (CLS) is a set of basic language features that .Net Languages needed to develop Applications and Services, which are compatible with the .Net Framework. When there is a situation to communicate Objects written in different .Net Complaint languages, those objects must expose the features that are common to all the languages.
CLS defines a subset of Common Type System (CTS). CTS is a standard that specifies how Type definitions and specific values of Types are represented in computer memory.CTS describes a set of types that can use different .Net languages have in common, which ensure that objects written in different languages can interact with each other.
For example CTS defines System.Int32, a 4 byte integer but C# defines int as an alias of System.Int32.
Microsoft .NET is tiered, modular, and hierarchal. Each tier of the .NET Framework is a layer of abstraction. .NET languages are the top tier and the most abstracted level. The common language runtime is the bottom tier, the least abstracted, and closest to the native environment. This is important since the common language runtime works closely with the operating environment to manage .NET application. Since higher tiers request services only from the lower tiers, .NET is hierarchal. The architectural layout of the .NET Framework is illustrated in following figure.
Over last few years there are so many things that have came into picture in the Microsoft .Net environment that help and support developer more and more. It has introduces many concepts, technology and design terms to extends its capabilities and potential aptitude. Microsoft .Net technology has been one of the most excellent boons for developers that provide rapid application development in true aspect.
Microsoft .NET technology has a great future ahead in all spheres ranging from Desktop Applications, Client Server Applications, Distributed Applications, Enterprise Applications, Web Applications, e-commerce store fronts and the most important Mobile Applications.
Architecture
If someone asks that what are the benefits of .Net to the end users and someone says that common language runtime, ASP.NET, WPF, WCF, LINQ, Parallel LINQ, XML integration, Garbage Collection, and so on. Is it an appropriate to say? Obviously no, it all helps to developer not to end users. The benefit of .Net is to users is the new generation of software that .NET introduces: software that runs anywhere, at anytime, on any platform, and from devices large and small.
The .NET Framework is a software framework. It includes a large library and provides language interoperability (each language can use code written in other languages) across several programming languages. Programs written for the .NET Framework execute in a software environment (as contrasted to hardware environment), known as the Common Language Runtime (CLR), an application virtual machine that provides important services such as security, memory management, and exception handling. The class library and the CLR together constitute the .NET Framework.
The .NET Framework's Base Class Library provides user interface, data access, database connectivity, cryptography, web application development, numeric algorithms, and network communications. The Common Language Runtime (CLR) serves as the execution engine of the .NET Framework. All .NET programs execute under the supervision of the CLR, guaranteeing certain properties and behaviors in the areas of memory management, security, and exception handling.
Common Language Specification (CLS) is a set of basic language features that .Net Languages needed to develop Applications and Services, which are compatible with the .Net Framework. When there is a situation to communicate Objects written in different .Net Complaint languages, those objects must expose the features that are common to all the languages.
CLS defines a subset of Common Type System (CTS). CTS is a standard that specifies how Type definitions and specific values of Types are represented in computer memory.CTS describes a set of types that can use different .Net languages have in common, which ensure that objects written in different languages can interact with each other.
For example CTS defines System.Int32, a 4 byte integer but C# defines int as an alias of System.Int32.
Microsoft .NET is tiered, modular, and hierarchal. Each tier of the .NET Framework is a layer of abstraction. .NET languages are the top tier and the most abstracted level. The common language runtime is the bottom tier, the least abstracted, and closest to the native environment. This is important since the common language runtime works closely with the operating environment to manage .NET application. Since higher tiers request services only from the lower tiers, .NET is hierarchal. The architectural layout of the .NET Framework is illustrated in following figure.
If we compare the architecture of .Net and Java we find almost same and strong architecture.
Sunday, September 16, 2012
Cross Browser
Introduction
There are several browsers and everyone does not use same browser and each one runs their own rendering engine. So it is not possible that our website or web application would run in each one of them. To avoid all these concept of cross browser came into the picture of internet world.
Cross browser is the concept or ability of website or web application or client-side scripting to work in the environment where they can get required features to run in any browser.
Don’t confuse with the multi browser where website or web application can only work in the environment where they have been guided to work. Cross browser make website or web application to be work in any environment.
Cross Browser Compatibility
Compatibility means functionality in different and alternative environment. It means how to perform equivalently under alternative condition.
There are several browsers and everyone does not use same browser and each one runs their own rendering engine. So it is not possible that our website or web application would run in each one of them. To avoid all these concept of cross browser came into the picture of internet world.
Cross browser is the concept or ability of website or web application or client-side scripting to work in the environment where they can get required features to run in any browser.
Don’t confuse with the multi browser where website or web application can only work in the environment where they have been guided to work. Cross browser make website or web application to be work in any environment.
Cross Browser Compatibility
Compatibility means functionality in different and alternative environment. It means how to perform equivalently under alternative condition.
Saturday, September 15, 2012
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