1.) What is data mining?
Data mining is the process of extracting potentially useful information from raw data. Data mining, the extraction of hidden predictive information from large databases, is a powerful new technology with great potential to support companies focus on the most important information in their data warehouses. Data mining tools predict future trends and behaviors, allowing businesses to make proactive, knowledge-driven decisions.
2.) What is the data type of the surrogate key?
1.It is always integer.
2.This is because we are generating a key and best performance comes only when keys are numeric. so they generate keys numerically only so that sorting is also quiet cheap for numbers compared to char,varchar..
3.) briefly state different between data ware house & data mart?
Dataware house is made up of many datamarts. DWH contain many subject areas. but data mart focuses on one subject area generally. e.g. If there will be DHW of bank then there can be one data mart for accounts, one for Loans etc. This is high level definitions. Metadata is data about data. e.g. if in data mart we are receving any file. then metadata will contain information like how many columns, file is fix width/elimted, ordering of fileds, dataypes of field etc...
4.) What is the difference between dependent data warehouse and independent data warehouse?
There is a third type of Datamart called Hybrid. The Hybrid datamart having source data from Operational systems or external files and central Datawarehouse as well. I will definitely check for Dependent and Independent Datawarehouses and update.
5.) how many clustered indexes can u create for a table in DWH?
By definition, a clustered index physically arranges all data in a table in a sequential manner. Since you can not have more than one physical arrangements of data in a table, you can have just one clustered index per table.
In case of truncate, all data is deleted without any transaction log entry, hence the unique ID can have the same values again, while in case of delete, the unique ID will have newer values in the new data load.
6.) What is Core Dimension?
Core Dimension is a Dimension table which is used dedicated for single fact table or Datamart. Conform Dimension is a Dimension table which is used across fact tables or Datamarts.
Data mining is the process of extracting potentially useful information from raw data. Data mining, the extraction of hidden predictive information from large databases, is a powerful new technology with great potential to support companies focus on the most important information in their data warehouses. Data mining tools predict future trends and behaviors, allowing businesses to make proactive, knowledge-driven decisions.
2.) What is the data type of the surrogate key?
1.It is always integer.
2.This is because we are generating a key and best performance comes only when keys are numeric. so they generate keys numerically only so that sorting is also quiet cheap for numbers compared to char,varchar..
3.) briefly state different between data ware house & data mart?
Dataware house is made up of many datamarts. DWH contain many subject areas. but data mart focuses on one subject area generally. e.g. If there will be DHW of bank then there can be one data mart for accounts, one for Loans etc. This is high level definitions. Metadata is data about data. e.g. if in data mart we are receving any file. then metadata will contain information like how many columns, file is fix width/elimted, ordering of fileds, dataypes of field etc...
4.) What is the difference between dependent data warehouse and independent data warehouse?
There is a third type of Datamart called Hybrid. The Hybrid datamart having source data from Operational systems or external files and central Datawarehouse as well. I will definitely check for Dependent and Independent Datawarehouses and update.
5.) how many clustered indexes can u create for a table in DWH?
By definition, a clustered index physically arranges all data in a table in a sequential manner. Since you can not have more than one physical arrangements of data in a table, you can have just one clustered index per table.
In case of truncate, all data is deleted without any transaction log entry, hence the unique ID can have the same values again, while in case of delete, the unique ID will have newer values in the new data load.
6.) What is Core Dimension?
Core Dimension is a Dimension table which is used dedicated for single fact table or Datamart. Conform Dimension is a Dimension table which is used across fact tables or Datamarts.
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