IT Interview Questions

1. Is XML case-sensitive?
   Yes.
   
2. What’s the difference between // comments, /* */ comments and /// comments?
   Single-line comments, multi-line comments, and XML documentation comments.
3. How do you generate documentation from the C# file commented properly with a command-line compiler?
   Compile it with the /doc switch.

ADO.NET and Database Questions

1. What is the role of the DataReader class in ADO.NET connections?
   It returns a read-only, forward-only rowset from the data source.  A DataReader provides fast access when a forward-only sequential read is needed.




2. What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET?
   SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix.  OLE-DB.NET is a .NET layer on top of the OLE layer, so it’s not as fastest and efficient as SqlServer.NET.
   

Assembly Questions

1. How is the DLL Hell problem solved in .NET?
   Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly.
2. What are the ways to deploy an assembly?
   An MSI installer, a CAB archive, and XCOPY command.
3. What is a satellite assembly?
   When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.

1. Explain the difference between BOOL, TINYINT and BIT. - Prior to MySQL 5.0.3: those are all synonyms. After MySQL 5.0.3: BIT data type can store 8 bytes of data and should be used for binary data.
2. Explain the difference between FLOAT, DOUBLE and REAL. - FLOATs store floating point numbers with 8 place accuracy and take up 4 bytes. DOUBLEs store floating point numbers with 16 place accuracy and take up 8 bytes. REAL is a synonym of FLOAT for now.

1. What is DDL, DML and DCL? - If you look at the large variety of SQL commands, they can be divided into three large subgroups. Data Definition Language deals with database schemas and descriptions of how the data should reside in the database, therefore language statements like CREATE TABLE or ALTER TABLE belong to DDL. DML deals with data manipulation, and therefore includes most common SQL statements such SELECT, INSERT, etc. Data Control Language includes commands such as GRANT, and mostly concerns with rights, permissions and other controls of the database system.