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Database Articles
Page 133 of 547
Data Modeling for Data Warehouse
Data modeling refers to the process of handling and designing the data model within a data warehouse platform. It consists of making an appropriate database schema so as to transfer the data that can be stored and of useful to user. Data warehouse modeling is used for two reasons, first is that relationship within the warehouse data can be visualised through the schema and second is that the cost is reduced and efficiency is increased with the help of well-designed schema which allow effective data warehouse structure to occur. Data modeling is different in data warehouse than in operational database ...
Read MoreData Mining:Data Attributes and Quality
Data Mining The process of extracting the data from a huge dataset that can be used for analysis and benefit of the organisation. This process helps in identifying patterns and managing relationship among the data to predict business problems. Data attributes An attribute can be defined as characteristics or property of an object. Object is described by attributes set and is referred to as a record of entity. Entity is described by a fraction of data i.e. attributes. For Example:In a Student database. (Name, id, Roll_no, Marks) are the attributes in provided database. Types of Attributes Nominal Attribute It only ...
Read MoreData Mining Process
The process of extracting the data from a huge dataset that can be used for analysis and benefit of the organization. Data mining process generally involves the following steps − Business understanding Business understanding and client objective is necessary. Clients needs are to be defined and then using the scenario, data mining goals are defined. Data understanding Data is collected from different sources and explored to understand the properties and characteristics of data. Data preparation The data that is being collected are now selected, cleaned, transformed, preprocessed and constructed so as to make it ready for analysis. This process takes ...
Read MoreData Mining multidimensional association rule
Association rule mining helps us to find relationships among large dataset. In Multidimensional association, Multidimensional association rule comprises of more than one aspect Numeric attributes should be discretized. Attributes can be unmitigated or quantitative. Quantitative characteristics are numeric and consolidate pecking order. Three approaches in mining multidimensional association rules are − Using static discretization of quantitative attributes Discretization happens earlier to mining and is static. Discretized attributes are treated as absolute and use an algorithm called apriori algorithm to search for all k-frequent predicate sets(k or k+1 table scans are required). Each subset of a frequent predicate set ...
Read MoreData Marts(storage component of HDFS)
Data mart is a storage component and only cares about some specific functional area of an organisation which are then taken care by a single department like marketing, sales, finance etc. Data Mart and Data Warehouse are both storage components of HDFS. Data Mart contains a subset of the data stored in the data warehouse. Frequently requested data can easily be accessed through data mart. Simple to Implement and cost is lower as compared to data warehouse. It is more open to change and its smaller size makes it quicker to build if any change in model occurs. ...
Read MoreData anomalies in DBMS
Anomalies means problems or inconsistency which happened during the operations performed on the table. There can be many reasons that anomaly occur for example, It occurs when data is stored multiple times unnecessarily in the database i.e. redundant data is present or it occur when all the data is stored in a single table. normalization is used to overcome the anomalies. the different type of anomalies are insertion, deletion and updation anomaly. Input The same input is used for all three anomalies. Student ID Name Age Branch Branch_Code Hod_name 1 A 17 Civil 101 Aman ...
Read MoreCurrent user function in SQL
It is used to return the name of the current user in sql database server. it does not accept any parameter. Syntax CURRENT_USER Current_user is the function used to get the name of current user Example 1 In this example, we are going to use the current_user function to get the current user name. Input Employee Emp_id Name Dept_name Salary 1 Monu IT 50000 2 Sonu HR 60000 3 Golu Security 70000 This database is currently used by amrendra. Code SELECT CURRENT_USER;#selected current user name Output Amrendra ...
Read MoreCreating materialised view using table definition in cassandra
A materialised is defined as a database object that contains the results of a particular query. It could be called as a subset of a table. Any changes in the base table would be reflected in the materialised view. Syntax CREATE MATERIALISED VIEW view_name AS SELECT * FROM table_name WHERE column_name IS NOT NULL PRIMARY KEY (provide_primary_key) Here, view_name is the name of the materialised view, table_name is the base table, column_name are the columns provide_primary_key are the primary keys for the base table. Example 1 In this example, we are gonna have a ...
Read MoreCreate, Alter & Drop schema
Create a schema Schema is basically the logical representation of the database. there is a default schema named dbo. Objects gets created inside a schema when ‘create schema’ statement is used. To provide access to other user after the schema is created, we need to impersoinate permissions. Syntax:The syntax to create a schema is − Create schema schema_name Here, we have created a schema named schema_name. Example 1: Granting permissions In this example, we are going to create a schema and grant permissions to have access to that. Algorithm Step 1 − Create a schema. Step 2 − ...
Read MoreCreate login in SQL Server
A login is a security check process to authenticate the user and make their data secure. In case of SQL, we need to login to connect to the server. Creating login for the server gives a security advantage. Also, security implications are to be understood and kept in mind while creating a login. A user will be granted the access of the database after user login is provided. Here, we are going to use various methods. Method 1: login with Password We are going to use simply the userid and password to login to the server. Syntax Create login ...
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