CoDe FuNn

What is SGA? The System Global Area in an Oracle database is the area in memory to facilitate the transfer of information between users. It holds the most recently requested structural information between users. It holds the most recently requested structural information about the database. The structure is database buffers, dictionary cache, redo log buffer and shared pool area. What is a shared pool? The data dictionary cache is stored in an area in SGA called the shared pool. This will allow sharing of parsed SQL statements among concurrent users. What is mean by Program Global Area (PGA)? It is area in memory that is used by a single Oracle user process. What is a data segment? Data segment are the physical areas within a database block in which the data associated with tables and clusters are stored. What are the factors causing the reparsing of SQL statements in SGA? Due to insufficient shared pool size. Monitor the ratio of the reloads takes place while executing SQL statem...

How does one see the uptime for a database? (for DBA ) Look at the following SQL query: SELECT to_char (startup_time,'DD-MON-YYYY HH24: MI: SS') "DB Startup Time" FROM sys.v_$instance; Marco Bergman provided the following alternative solution: SELECT to_char (logon_time,'Dy dd Mon HH24: MI: SS') "DB Startup Time" FROM sys.v_$session WHERE Sid=1 /* this is pmon */ / Users still running on Oracle 7 can try one of the following queries: Column STARTED format a18 head 'STARTUP TIME' Select C.INSTANCE, to_date (JUL.VALUE, 'J') || to_char (floor (SEC.VALUE/3600), '09') || ':' -- || Substr (to_char (mod (SEC.VALUE/60, 60), '09'), 2, 2) || Substr (to_char (floor (mod (SEC.VALUE/60, 60)), '09'), 2, 2) || '.' || Substr (to_char (mod (SEC.VALUE, 60), '09'), 2, 2) STARTED from SYS.V_$INSTANCE JUL, SYS.V_$INSTANCE SEC, SYS.V_$THREAD C Where JUL.KEY like '%JULIAN%' and SEC.KEY like '%...

Define Transaction ? A Transaction is a logical unit of work that comprises one or more SQL statements executed by a single user. What is Read-Only Transaction ? A Read-Only transaction ensures that the results of each query executed in the transaction are consistant with respect to the same point in time. What is a deadlock ? Explain . Two processes waiting to update the rows of a table which are locked by the other process then deadlock arises. In a database environment this will often happen because of not issuing proper row lock commands. Poor design of front-end application may cause this situation and the performance of server will reduce drastically. These locks will be released automatically when a commit/rollback operation performed or any one of this processes being killed externally. What is a Schema ? The set of objects owned by user account is called the schema. What is a cluster Key ? The related columns of the tables are called the cluster key. The cluste...

Can a view based on another view? Yes. What are the advantages of views? - Provide an additional level of table security, by restricting access to a predetermined set of rows and columns of a table. - Hide data complexity. - Simplify commands for the user. - Present the data in a different perspective from that of the base table. - Store complex queries. What is an Oracle sequence? A sequence generates a serial list of unique numbers for numerical columns of a database's tables. What is a synonym? A synonym is an alias for a table, view, sequence or program unit. What are the types of synonyms? There are two types of synonyms private and public. What is a private synonym? Only its owner can access a private synonym. What is a public synonym? Any database user can access a public synonym. What are synonyms used for? - Mask the real name and owner of an object. - Provide public access to an object - Provide location transparency for tables, views or program units of a remote dat...

What are the components of physical database structure of Oracle database? Oracle database is comprised of three types of files. One or more datafiles, two are more redo log files, and one or more control files. What are the components of logical database structure of Oracle database? There are tablespaces and database's schema objects. What is a tablespace? A database is divided into Logical Storage Unit called tablespaces. A tablespace is used to grouped related logical structures together. What is SYSTEM tablespace and when is it created? Every Oracle database contains a tablespace named SYSTEM, which is automatically created when the database is created. The SYSTEM tablespace always contains the data dictionary tables for the entire database. Explain the relationship among database, tablespace and data file ? Each databases logically divided into one or more tablespaces one or more data files are explicitly created for each tablespace. What is schema? A schema is ...

Describe the advantages of writing a managed code application instead of unmanaged one. What’s involved in certain piece of code being managed? The advantages include automatic garbage collection, memory management, support for versioning and security. These advantages are provided through .NET FCL and CLR, while with the unmanaged code similar capabilities had to be implemented through third-party libraries or as a part of the application itself. Are COM objects managed or unmanaged? Since COM objects were written before .NET, apparently they are unmanaged. Any code not written in the Microsoft .NET framework environment is UNMANAGED. So naturally COM+ is unmanaged because it is written in Visual Basic 6. So can a COM object talk to a .NET object? Yes, through Runtime Callable Wrapper (RCW) or PInvoke. How do you generate an RCW from a COM object? Use the Type Library Import utility shipped with SDK. tlbimp COMobject.dll /out:.NETobject.dll or reference the COM library...

What do you know about .NET assemblies? Assemblies are the smallest units of versioning and deployment in the .NET application. Assemblies are also the building blocks for programs such as Web services, Windows services, serviced components, and .NET remoting applications. What’s the difference between private and shared assembly? Private assembly is used inside an application only and does not have to be identified by a strong name. Shared assembly can be used by multiple applications and has to have a strong name. What’s a strong name? A strong name includes the name of the assembly, version number, culture identity, and a public key token. How can you tell the application to look for assemblies at the locations other than its own install? Use the directive in the XML .config file for a given application. should do the trick. Or you can add additional search paths in the Properties box of the deployed application. How can you debug failed assembly binds? Use the Assembl...