Interview Questions and Answers PDF

Truncate: It is a DDL command, used to delete tables or clusters. Since it is a DDL command hence it is auto commit and Rollback can’t be performed. It is faster than delete. Delete: It is DML command, generally used to delete a record, clusters or tables. Rollback command can be performed , in order to retrieve the earlier deleted things. To make deleted things permanently, “commit” command should be used.

Dependency analysis will answer the questions regarding datalinage. That is where does the data come from,what applications produce and depend on this data etc. We can retrieve the maximum (surrogate key) from the existing data,the by using scan or next_in_sequence/reformat we can generate further sequence for new records.

By using rollup we cant generate cumulative summary records for that we will be using scan.

Do you mean by merging Gui map files in WR.If so, by merging GUI map files in GUI map editor it wont create corresponding test script.without test script you cant run a file.So it is impossible to run a file by merging 2 GUI map files.

The best way would be to perform join at the database, the classical way is when we have two tables that we can bring together by making placing a join component between them. Alternately we can write a query to make the join at the level of a database. The advantage is that only one hit is sent to the database instead of two (the classical method). This makes a real difference in improving performance.

Writing of a wrapper will help us run sequential running of two graphs, for instance in order to do this the user must use that feed that was generated by the first graph into the next graph, and for multiple use into the next graph and so on.

Their role is seen when we are trying to use the same graph many times for various files, in this way we must set parameters for the graph, which get replaced anyway during run. So we can keep one graph version for different files and not different versions.

Both API and utility modes are used as connection interfaces to the databases for the purpose of performing specific tasks required by the user. They allows us to easily access different functions that the vendor put for use. The role of each function is related to the nature of the databases. The difference between the two modes is that API is known to be slower but offers a higher range of flexibility than the utility mode. Also API is considered to be a more diagnostic feature.

The main reason is network traffic reduction. Because stored procedures are precompiled SQL blocks, the time of execution can be reduced. In this way the application performance is higher, being stored in the database the procedure will be called by the application and execute faster than in the case is not already compiled. They also provide reusability for different other applications.

The limit parameter is representing how much reject events exist and is an integer, while the limit parameter is the rate of reject events that the records processed has, it is a real number.

Driving port is usually meant for graph performance enhancement.

The partitioning with key (also called hash partition) is partitioning method used when we have diverse keys. The technique is used basically in the processing of parallel data. On the other hand round robin partitioning is a technique that allows us to distribute the data on every destination partition uniformly. While in the case of partitioning with key we can have large data skew due to large key volume, in the case of using round robin partitioning the skew is zero.

It is a transform component in which we find different packages.

The supported layouts are the serial and the parallel and a graph can include them both. The parallel layouts is related to the parallelism degree.

Scan components make a total series of records while RollUp components summarize groups of data records.

The similarity between these two types is that they are both used for database connectivity. The difference is the usage in Informix Database of the CFG file type and the DB config files are used in SQL Server or Oracle.

The Standard Environment is the type of environment with more than one project that is private and another public one.

Some calculations lead to approximately eight MB plus the MAX_CORE and the phase file size.

What phasing does is deleting the intermediate (temporary) files before a new phase begins which is different from checkpointing. The checkpoints keep the temporary files until we finish the graph, so in case of failing we can restore the last good process. The phase doesn’t have this advantage.

The purpose of this function is usually to store mappings and this is very useful because the rewriting of code takes time and the XFR spares us of this effort.