Data Stage FAQ's -1

11 What are types of Hashed File? Hashed File is classified broadly into 2 types. a) Static - Sub divided into 17 types based on Primary Key Pattern. b) Dynamic - sub divided into 2 types i) Gen... 12 Containers : Usage and Types? Container is a collection of stages used for the purpose of Reusability. There are 2 types of Containers. a) Local Container: Job Specific b) Shared Container: Used in any job wit... 13 Compare and Contrast ODBC and Plug-In stages? ODBC : a) Poor Performance. b) Can be used for Variety of Databases. c) Can handle Stored Procedures. Plug-In: a) Good Performance. b) Database specific.(Only one database) <... 14 How to run a Shell Script within the scope of a Data stage job? By using "ExcecSH" command at Before/After job properties. 15 How to handle Date convertions in Datastage? Convert a mm/dd/yyyy format to yyyy-dd-mm? We use a) "Iconv" function - Internal Convertion. b) "Oconv" function - External Convertion. Function to convert mm/dd/yyyy format to yyyy-dd-mm is Oconv(Iconv... 16 Types of Parallel Processing? Parallel Processing is broadly classified into 2 types. a) SMP - Symmetrical Multi Processing. b) MPP - Massive Parallel Processing. 17 What does a Config File in parallel extender consist of? Config file consists of the following. a) Number of Processes or Nodes. b) Actual Disk Storage Location. 18 Functionality of Link Partitioner and Link Collector? Link Partitioner : It actually splits data into various partitions or data flows using various partition methods . Link Collector : It collects the data coming from partitions, merges ... 19 How did u connect to DB2 in your last project? Using DB2 ODBC drivers. 20 What are OConv () and Iconv () functions and where are they used? IConv() - Converts a string to an internal storage formatOConv() - Converts an expression to an output format. 21 What are Routines and where/how are they written and have you written any routines before? Routines are stored in the Routines branch of the DataStage Repository, where you can create, view or edit. The following are different types of routines: 1) Transform functions&nb... 22) Dimension Modelling types along with their significance Data Modelling is Broadly classified into 2 types. a) E-R Diagrams (Entity - Relatioships). b) Dimensional Modelling. 23) Dimensional modelling is again sub divided into 2 types. a)Star Schema - Simple & Much Faster. Denormalized form. b)Snowflake Schema - Complex with more Granularity. More normalized form. 24) Importance of Surrogate Key in Data warehousing? Surrogate Key is a Primary Key for a Dimension table. Most importance of using it is it is independent of underlying database. i.e Surrogate Key is not affected by the changes going on with a databas... 25) Differentiate Database data and Data warehouse data? Data in a Database is a) Detailed or Transactional b) Both Readable and Writable. c) Current. 26) What is the flow of loading data into fact & dimensional tables? Fact table - Table with Collection of Foreign Keys corresponding to the Primary Keys in Dimensional table. Consists of fields with numeric values. Dimension table - Table with Unique Primary Key... 27) Orchestrate Vs Datastage Parallel Extender? Orchestrate itself is an ETL tool with extensive parallel processing capabilities and running on UNIX platform. Datastage used Orchestrate with Datastage XE (Beta version of 6.0) to incorporate the p... 28) Differentiate Primary Key and Partition Key? Primary Key is a combination of unique and not null. It can be a collection of key values called as composite primary key. Partition Key is a just a part of Primary Key. There are several methods of ... 29) How do you execute datastage job from command line prompt? Using "dsjob" command as follows. dsjob -run -jobstatus projectname jobname 30) What are Stage Variables, Derivations and Constants? Stage Variable - An intermediate processing variable that retains value during read and doesnt pass the value into target column. Derivation - Expression that specifies value to be passed o... 31) What is the default cache size? How do you change the cache size if needed? Default cache size is 256 MB. We can incraese it by going into Datastage Administrator and selecting the Tunable Tab and specify the cache size over there.