BI DW Assessement

March 31, 2018 | Author: Ur's Gopinath | Category: Data Warehouse, Sql, Databases, Relational Database, Conceptual Model


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TopicQuestions Option (A) Option (B) DM A data warehouse is which of the following? Can be updated by end users Contains numerous naming conventions and formats. DM A star schema has what type of relationship between a dimension and fact table? Many-to-many One-to-one DM Fact tables are which of the following? Completely demoralized Partially demoralized DM A snowflake schema is which of the following types of tables? Fact Dimension DM A goal of data mining includes which of the following? To explain some observed event or condition To confirm that data exists DM OLAP databases are called decision support system ? TRUE FALSE DM In Star Schema Dimension tables are Short and Fat Long and Thin DM The data in Data Warehouse is generally Clean Data Dirty Data DM Choose two Ralph Kimball believes that portions of data can be combined based on relevance of data and can be used for reporting Inmon believes that portions of data can be combined based on relevance of data and can be used for reporting DM In which type of SCD(Slowly changing dimensions) do we preserve history of data: Type One Type Two ETL During ETL load we generally have Unsorted data for Aggregator Sorted data for Aggregator DM Sequence of jobs to load data in to warehouse First load data into fact tables then dimension tables, then Aggregates if any First load data into dimension tables, then fact tables, then Aggregates if any DM Snowflaking means Normalizing the data Denormalizing the data OLAP Drill Across generally use the following join to generate report Self Join Inner Join DM In general data in Data Warehousing is Normalized Denormalized DM Consolidated data mart is First level data mart Second level data mart DM In 4 step dimensional process, declaring gain of business process is First Step Second Step DM Dimensions are Confirmed when They are different They are either same or one is subset of another DM You need to create an index on the SALES table, which is 10 GB in size. You want your index to be spread across many tablespaces, decreasing contention for index lookup, and increasing scalability and manageability.Which type of index would be best for this table? bitmap unique DM Which of the following statements is true? A data warehouse is useful to all organisations that currently use OLTP's A data warehouse is valuable only if the organisation has an interest in analysing historical data. DM Analytical processing is the act of using software to analyse highly consolidated data, often to view the changes over time. the act of exporting data into a spreadsheet for analysis DM Which of the following statements is true? The fact table of a data warehouse is the main store of descriptions of the transactions stored in a DWH The fact table of a data warehouse is the main store of all of the recorded transactions over time. DM Which of the following is associated with a data warehouse A relation A flat file DM Which of the following statements is true? The more data a data warehouse has, the better it is A data warehouse automatically makes a copy of every transaction recorded in an OLTP system DM A data warehouse must import data from transactional systems whenever significant changes occur in the transactional data. takes regular copies of transaction data DM Granularity refers to The number of fact tables in a data warehouse The level of detail of the data descriptions held in a data warehouse DM Dimensionality refers to The level of detail of data that is held in the fact table The data that describes the transactions in the fact table. DM The main organisational justification for implementing a data warehouse is to provide lagre scale transaction processing Cheaper ways of handling transactions OLAP OLTP stands for On Line Transaction Processing On Line Terminal Protocol DM Data in a data warehouse in a flat file format must be in normalised form to at least 3NF DM A data warehouse needs to be time varient Subject orientated DM Transaction processing is the act of processing individual transactions the act of analysing each transaction to verify that it is valid OLAP OLAP stands for On Line Analytical Protocol On Line Abstraction Processing DM What is a formal way to express data relationships to a database management system? Attributes Entity identifier DM What is a technique for documenting the relationships between entities in a database environment? Attributes Entity identifier DM What indicates having the potential to contain more than one value for an attribute at any given time? Constraint Single-valued DM Which relationship is between two entities in which an instance of entity A can be related to zero, one, or more instances of entity B and entity B can be related to zero, one, or more instances of entity A? One-to-many relationship One-to-one relationship DM Which of the following uses a series of logically related two-dimensional tables or files to store information in the form of a database? Database Database management system OLAP All of the following terms describe OLAP, except The gathering of input information Processing input information DM Which tool is used to help an organization build and use business intelligence? Data warehouse Data mining tools DM What does the data dictionary identify? Field names Field types DM Which of the following is a data manipulation tool? File generators Query by example tool DM When gathering business information requirements, you should focus only on the requirements provided by the business groups. TRUE FALSE OLAP One difference between the design of online transaction processing (OLTP) and online analytical processing (OLAP) systems is that the OLTP system design is optimized for getting data into the database. TRUE FALSE DM Designing a data warehouse in first normal form (1NF) is not recommended. TRUE FALSE DM Cardinality is defined as the number of relationships existing between entities. TRUE FALSE DM It is not important to include metadata when designing a data warehouse. TRUE FALSE DM There is no need to include a time dimension in the data warehouse. TRUE FALSE DM The level of granularity you choose for the time dimension has no significant impact on the size of your database. TRUE FALSE DM Surrogate keys are generated on tables in the data warehouse after the table is populated. TRUE FALSE DM To improve performance, all tables in the data warehouse should be indexed. TRUE FALSE DM Fact tables are often referred to as the measures of business performance. TRUE FALSE DM Dimension tables are used to provide descriptions of the business subjects and descriptive information about each row in the fact table. TRUE FALSE DM A high level of granularity means more detail; a low level of granularity mean less detail. TRUE FALSE DM One method of managing the history in dimension tables is to drop the dimension and rebuild the table from scratch. TRUE FALSE DM You do not need to be concerned with maintaining the history of changing data in the dimension tables. TRUE FALSE DM Effective use of summaries is the best technique for improving performance in data warehouses. TRUE FALSE DM Summary data cannot be combined with detailed fact data. TRUE FALSE DM When choosing a level of summarization, there are two approaches: summarizing the entire dimension, or summarizing part of the dimension and partially improving performance TRUE FALSE DM Table partitioning splits the storage of a table into smaller individual units. TRUE FALSE DM Denormalization is the factor that increases the sparseness in a database. TRUE FALSE OLAP What are the actual data values that occupy the cells as defined by the dimensions selected? Nesting Aggregation OLAP The term that defines filtering data in an OLAP cube is ___________ . dicing slicing OLAP What is an item that matches a specific description or classification? Category Measure OLAP The cube structure in OLAP achieves the __________ functionality. shared information OLAP Aggregation provides OLAP with __________ multidimensional data pre-calculated data OLAP What is the acronym that defines OLAP? FHTMI FASMI OLAP __________ in OLAP allows you to define a subcube of the original space. Dicing Slicing OLAP What term in OLAP defines changing the dimensional orientation of the report from the cube data? Dicing Slicing OLAP The _________ in OLAP enable you to drill-up or drill-down to view different levels of detail about your data. dimensions measures OLAP When you nest in OLAP, you _________ . select multiple cube aggregations select multiple cube measures ETL Which of the following describes ETL? A process that transforms information using a common set of enterprise definitions A process that loads information into a data warehouse DM What is data mining A particular attribute of information The common term for the representation of multidimensional information DM A collection of related data fields is called a ____. byte record DM A DBMS is a(n) ____. interface between the database and application programs data repository DM A(n) ____ is a generalized class of people, places, or things for which data is collected, stored, and maintained record entity DM Which attribute would make the best primary key? Social security number Last name DM The ____ data model follows a treelike structure. distributed hierarchical DM The most popular database model currently in use is the ____. relational model hierarchical model DM A primary key is a field or set of fields that uniquely identifies a record. TRUE FALSE DM One of the goals of a DBMS is to increase data redundancy thereby making it less vulnerable to hackers. TRUE FALSE DM A Data Warehouse would most likely be part of a(n) ERP System Small MIS System DM Data Mining would most likely be used to streamline a Transaction Processing System to model data in a DBMS DM Which of the following is a valid key field A Book Title House number + Street Name DM A Table Can only store data of one type Consists of Alphanumeric data DM A RDBMS cannot store data without knowing the data type. Which of the following statements are true? A Logical data type can store three values, TRUE, UNKNOWN and FALSE Numerical data can be stored in different formats DM A FLAT FILE database management system is A database design that only has one table in it A DBMS that can only have simple data tables in it DM Assume you are extending the design of The College Student Records System to include details on each classroom. The college is never likely to have more than ten classrooms and definitely not ever going to have more than 25 classrooms. What data type would you select Numeric - Byte Numeric - Single OLAP A report must be exported to a word processor for printing be based on an underlying data source (a table or a query) OLAP The layout of a report is independant of the number of records held in a table or query True FALSE OLAP A report is used to produce output that is ready for e-mailing produce output that is ready for publication on the Web (HTML) DM The rule that prohibits transitive dependencies is third normal form first normal form DM The rule that requires that each non-key field (attribute) should be fully functionally dependent on the primary key is Third Normal Form First Normal Form DM The rule that specifies that there should be no repeating fields and that fields should be atomic is third normal form second normal form DM The process of combining two tables in a relational database is known as a Join a Combine DM The ER model is meant to enable low level descriptions of data replace relational design DM The Entity Relation Model models Entities Relationships DM Which of the following statements best decribes the function of an entity relation model? An ER model provides a view of the logic of the data and not the physical implementation. An ER model is concerned primarily with a physical implementation of the data and secondly with the logical view DM SQL stands for Sequential Question Language Structured Query Language DM Which of the following are elements of SQL? Data Query Language Data Definition Language DM Consider the table (STUDREC). Which of the following statements will list columns INIT, SNAME, GENDER and KIDS (in that order) for all students who have more then 1 child. SELECT init, sname, gender, kids FROM studrec WHERE kids <1; SELECT init, sname, gender, kids FROM studrec WHERE kids >1; OLAP A typical data warehouse consists of … Staging area Data Marts OLAP What are the three layers of Data warehouse architecture? Data staging layer, Data Extract layer, Data transactional layer Data Modelling layer, Data Accesses layer, Data Storage layer OLAP Staging Area comes under which layer? Data Storage layer Data Access layer OLAP What are Limitations of Traditional techniques ? Extensive programming Redundant reporting OLAP Different categories of Data Access are? Web Access Data Mining OLAP OLAP stands for Online Access Processing Online Analytic Processing OLAP A process that uses a variety of statistical and artificial intelligence frameworks to discover patterns and relationships in data Data Access Process Data Mining Process OLAP A category of data access solutions in which information is viewed through a web browser Data Access Process Data Mining Process OLAP What is importance of Data Access? Businesses today face challenges like Data Access is the ‘last mile’ that enables decision makers to OLAP What are different types of reporting? Transaction Systems Reporting Enterprise Data Warehouse Reporting OLAP In Transaction Systems Reporting, Reporting Tool has a native connectivity to ? Views Tables OLAP An enterprise data warehouse (EDW) is designed to To combine data from multiple OLTP systems To provide consolidated and cleansed data to an array of data marts OLAP Examples of Managed Query Tool Business Objects MS Query OLAP Which are the OLAP features ? Multidimensional viewing Capabilities Time Intelligence - Time Series analysis OLAP OLAP system is Decision support Relatively standardized and simple queries returning relatively few records OLAP What is measure? Is not a number represents factual data OLAP What is ROLAP? Data is stored in multidimensional cubes Support for large databases with good performance SQL Which one is DDL command? Insert Update SQL How many types of Normalization rules are there? 4 5 SQL Which are pseudocolumns CURRVAL NEXTVAL SQL Can you use select in FROM clause of SQL select ? YES NO SQL Describe the use of %ROWTYPE in PL/SQL ? It allows you to associates a variable with a single column type It allows you to associate a variable with an entire table row SQL How many types of triggers are there? 9 10 SQL What is the default ordering of an ORDER BY clause in a SELECT statement? Descending Ascending SQL Union All returns All rows selected by either query All rows selected by either query and including duplicates ETL What is ETL process? ETL is the set of processes by which data is extracted from various sources, transformed and loaded into target systems ETL is the set of processes by which data is extracted from various sources and loaded into target systems ETL What is Importance of ETL? Closely integrated with RDBMS’s High speed loading of target data warehouses ETL Which are ETL Activities ? Data Extraction, Data transformation, Data loading Data Extraction, Data Extraction – Cleanup, Data loading ETL Data Extraction Methods are Incremental Extraction Real Time Extraction ETL Which are the examples of ETL tools? Informatica PowerCenter Ab Initio ETL What is Bulk Load? Format of Archived data different from operational data It limits your ability to recover because no database logging occurs ETL Which one is not GUI based Scheduler ? Tool Specific Autosys ETL What do you mean by Source alteration stage in ETL ? perform a variety of transformations unique to the source, depending on business requirements performs the access and extraction of data from the source system and builds a temporal view of the data at the time of extraction ETL What are the different types of Commit intervals? Target-based commit Source-based commit ETL Which is the first step of the ETL process ? Data Extraction – Cleanup Data Extraction ETL Which is not pros of Batch Extraction ? Quick and relatively easy to write scripts for doing exports and imports Does not usually require additional hardware ETL Which tool does not support Change-Data- Capture Feature ? Ascential Data Stage XE Informatica PowerCenter DW What is Data Warehouse ? Data Warehouse is integarted of data in support of management's decisions A data warehouse is a subject- oriented, integrated, nonvolatile, time-variant collection of data in support of management's decisions DW What is the Need of Data Warehousing ? To store Operational Data Better business intelligence for end-users DW Which one is not Characteristic of Data Mart ? Restrictive, non extensible Short life/tactical DW Which is the information need for recent data ? ODS OLTP DW What type of Data Structure Characteristic does Data Warehousing has ? Detailed Summarized DW What are Components of a Data Warehouse Architecture ? Data Cleansing tool ETL tool DW What is use of Data Cleaning Tools ? Clean up source data in-place on the host Generate and maintain centralized metadata DW What is the use of Data Mining Tools ? Slice and Dice What If analysis DM What is Database ? A known fact that can be recorded and that have implicit meaning The data is perceived by the user as tables DM What is Data Model ? A collection of concepts that can be used to describe the structure of a database Representation of a set of business requirements in a standard structured framework understood by the users DM Which Data Modelling approach suit for corporate data Warehouse ? Dimensional Approach Entity Relational Approach DM What are the different types of relationship notations ? IEX IDFIX DM What is Physical Data Model ? Conceptual Geared for performance and may consists of redundant data DM What are different types of Data Model ? Physical model, Logical model, Hybrid model DM Can we have multiple foreign keys in a table ? TRUE FALSE Option (C) Option (D) Answer s Organized around important subject areas. Contains only current data. C One-to-many All of the above B Completely normalized Partially normalized C Helper All of the above D To analyze data for expected relationships To create a new data warehouse A A Long and Fat Short and thin A Clean and Dirty Data None of above A Inmon believes that DW is built and should be used for reporting. Ralph Kimball believes that DW is built and should be used for reporting. B and D Type Three None of above B Does not matter if we use Sorted or Unsorted data for Aggregation None of the Above B First Aggregates then load data into dimension tables, then fact tables Does not matter if we load either of fact, dimensions, or aggregates B None of Above A Outer Join None of the Above C None of Above C All of these None of Above B Third Step Fourth Step B When they can be compared mathematically None of these B partitioned reverse Key C A data warehouse is valuable to thiose organisations that need to keep an audit trail of their activities A data warehouse is necessary to all those organisations that are using relational OLTP's B the act of using a relational database to produce reports giving data summaries on a regular basis (e.g. monthly) the act of sumarising data on a regular basis (e.g. month end summaries) A A fact table describes the granularity of data held in a DWH A fact table describes the transactions stored in a DWH B A hierachical and/or network structure A star schema D A data warehouse is a relatively straighttforward thing to set up. Adding data for the sake of it may well degrade the effectiveness of data warehouseing analysis D takes regular copies of transaction data and stores it in a way that is optimised for query and reporting has to work on live transactional data to provide up to date and vaild results C The level of detail of the data stored in a data warehouse. The number of dimensions in a data warehouse C The level of detail that is held in the Data Warehouse The number of dimension tables that exist in a star schema B Storing large volumes of data Decision support D On Line Terminal Processing On Line Transaction Protocol A can be normalised but often isn't must be in normalised form to at least 2NF C Capable of integrating data from a wide variety of sources non-volatile A,B,C,D the act of analysing transactions on a regular basis (e.g. monthly) the act of processing, recording and storing individual transactions in a database D On Line Abstraction Protocol On Line Analytical Processing D Data model Entity-relationship diagram C Data model Entity-relationship diagram D All of the above None of the above D Many-to-many relationship Many-to-one relationship C Data warehouse None of the above D Updating existing information to reflect to the gathered and processed information None of the above D Database management systems All of the above D Field formats All of the above D Structure question language All of the above B B A B A B B B B B A A A B B A B A A A Dimensions Measures D rotating nesting B Dimension Nest A collection multidimensional D nested data slow data retrieval B ASFMI MASHF B Rotating Nesting A Rotating Nesting C nesting aggregation A select multiple cube dimensions select multiple cube slices C A process that extracts information from internal and external databases All of the above D The process of analyzing data to extract information not offered by the raw data alone Uses a variety of techniques to find patterns and relationships in large volumes of information and infer rules from them that predict future behavior and guide decision making C character bit B knowledge base unique group of records A attribute file B First name Age A network relational B network model object model A A B DBMS Expert system A to help transform data into useful information that can be used by a DSS to help transform data from different sources so that they can be stored in a single Data Warehouse. C Car Registration number Initials + Family Name + Date of Birth C Consists of Rows and Columns Cannot be empty B Some DBMS's can use DATE data types A Character (Text) data type can contain 0,1,2,3,4,5,6,7,8 and 9 B,C,D A DBMS that can only have one table in it A DBMS that contains records that have a large number of fields in them C Numeric - Integer Numeric - Long integer A Be redefined each time it is used be password protected B A produce output that is formatted for display on a computer screen produce output formatted for print D second normal form None of the Above A Second Normal Form None of the Above C first normal form None of the Above C a Relate a Construc A be close to a users perception of the data enable detailed descriptions of data query processing C Entities, Relationships and Processes Entities and Relationships D An ER model is entirely concerned with modelling the physical implemetation An ER model is concerned primarily with a logical view of the data and secondly with the physical implementation A Structured Question Language Sequential Query Language B Data Modification Language Data Manipulation Language A,B,D SELECT init, sname, gender, kids FROM studrec WHERE kids >'1'; SELECT init sname, gender, kids FROM studrec WHERE kids >1; D Analytical environment All of the above A Data Extraction layer, Data Accesses layer, Data Storage layer None C Data Extract layer None D SQL does not have a natural way of providing flexible view reorganizations that will transpose the data All of the above D Both A and B None C Both A and B None B Web Access Process None B Web Access Process Reporting C Prompt, reliable data access All of the above D Both A and B None C OLAP OLTP D Both A and B None C Microsoft Access All of the above A Only A Both A and B D Both A and B None A description of subject Both B and C B Good to access pre-aggregated data Compilation intensive architecture B Drop Select C 6 7 B ROWID All of the above D A It allows you to associate a variable with an entire table column Both A and C B 11 12 D B All distinct rows selected by both queries All rows selected by the first query but not the seconds B Both A and B None A Both A and B Only A C Data Extraction, Data loading Data Extraction, Data transformation, Data Extraction – Cleanup, Data loading D Full Extraction All of the above D Business Objects Both A and B D Lengthy and Complex process All of the above B CRON jobs All of the above C performs final formatting of data to produce load-ready files for the target table; identifies and segregates rows to be inserted vs. updated (if applicable); applies remaining technical meta data tagging; and processes data into the RDBMS final stage, uses the load- ready files from Stage 4 to build aggregation tables needed to improve query performance against the warehouse A Only A Both A and B D Data transformation Data loading B Not event driven--does not facilitate notification or change in another application at the time of a change in first application Almost all applications provide utilities for exporting and importing C Ab Initio All of the above B Both A and B None B Used by Operational users Both B and C B Project Orientation Flexible, extensible D OLAP All of the above A Detailed and Summarized Detailed and lightly summarized C Data Modelling tool All of the above D Automatic generation of data extract programs All of the above A Dill Down Static Reports B It is designed, built, and populated with data for a specific purpose All of the above C Both A and B None A Both A and B None B IE Both B and C C Both A and B None B Conceptual model Both A and C D A
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