Data integration in data warehouse

Data Warehouse Concepts, Design, and Data Integration

An enterprise uses an average of applicationsalong with many other on-premise systems. This means that you can have about a thousand source systems from different vendors, each storing data differently. When data is scattered across so many systems throughout the enterprise, how do you make sense out of it? If you have a little know-how of the data management realm, you already know that data integration is the answer. The simplest and the earliest data integration approach, it refers to exporting data from a source system in a file and then importing it to your target system. You could export data from individual campaigns in a. CSV file and import it to your sales application manually. The other option is to develop a custom program that automatically exports data from specified campaigns and imports it at a pre-configured time. Perhaps your marketing system has separate fields for FirstName and LastName while the sales app only has the FullName field. Another major limitation is that you can only export and import data to and from two systems at a time. In enterprise environments, you could potentially be required to integrate data from hundreds of applications. Once you start thinking about data integration on a large scale, ETL becomes an viable option, one that has been around for decades due to its utility and scalability. As is clear from the abbreviation, the ETL process revolves around Extracting the desired data from the source system, Transforming to blend and convert it into a consistent format, and finally Loading it to the target system. The entire process is largely automated, with modern tools offering a workflow creation utility where you can specify the source and destination systems, define transformations and business rules to be applied, and configure how you want the data to be read and written. The workflow could include multiple integrations from a variety of source systems. Once completed, you can execute the workflow to run ETL jobs behind the scenes. While ETL does have its own set of challenges, many of them are not properly understood. Take your workflows deeper, and could even create an Enterprise Data Warehouse or data marts if you start thinking of your integration flows on a macro level. Another ETL misconception is that it only allows data to be loaded in batches, on fixed hourly, daily, or weekly frequencies. While ETL has been around since the 70s, point-to-point integrations remained popular until the s when the increasing number of enterprise applications made the approach unsustainable. This is clearly impractical, more so when you account for maintenance. This model centers on a hub-and-spoke approach to build point-to-point integrations. ESB software offer a pre-built environment that allows rapid development of point-to-point connections in an enterprise while allowing the capability to develop transformations, error-handling, and performance metrics within that same environment. The result is an integrated layer of services, with business intelligence applications invoking services from the primary layer. This solution has made point-to-point integrations viable again for complex integrations, but still requires IT involvement. The data virtualization approach is becoming increasingly popular because it eliminates physical data movement altogether. Data sits where it is created in source systems, and queries are run on a virtualization layer that insulates users from the technical details of accessing data. Queries could be from your reporting application, or any business intelligence system that retrieves data, blends it, and displays results to users. For the connecting applications, the virtualization layer looks like a single, consolidated database, but in reality, data is accessed from different source systems. Data virtualization software today also support caching mechanisms, so you can make it available when running multiple queries on the same sets of data, which reduces time and effort. Rather, it complements the data warehouse by providing convenient access to unstructured data types. Ideally, your chosen solution should support multiple data integration types for building integrations as per your business needs and have supporting automation features to ramp up the process. Your email address will not be published. Yes, add me to your mailing list. This site uses functional cookies and external scripts to improve your experience. Which cookies and scripts are used and how they impact your visit is specified on the left. You may change your settings at any time. Your choices will not impact your visit. NOTE: These settings will only apply to the browser and device you are currently using. Search for: Search.

Data Warehouse


Having a discussion about data integration might seem simple enough. However the term can be interpreted quite differently, depending on the context. Data integration in the purest sense is about carefully and methodically blending data from different sources, making it more useful and valuable than it was before. There are methods of bringing data together into an integrated view and there are techniques for bringing data together physically, for an integration version. Below are a few common data integration approaches. Data consolidation physically brings data together from several separate systems, creating a version of the consolidated data in one data store. Often the goal of data consolidation is to reduce the number of data storage locations. Extract, transform, and load ETL technology supports data consolidation. ETL pulls data from sources, transforms it into an understandable format, and then transfers it to another database or data warehouse. The ETL process cleans, filters, and transforms data, and then applies business rules before data populates the new source. Data propagation is the use of applications to copy data from one location to another. It is event-driven and can be done synchronously or asynchronously. Most synchronous data propagation supports a two-way data exchange between the source and the target. EAI integrates application systems for the exchange of messages and transactions. It is often used for real-time business transaction processing. EDR typically transfers large amounts of data between databases, instead of applications. Virtualization uses an interface to provide a near real-time, unified view of data from disparate sources with different data models. Data can be viewed in one location, but is not stored in that single location. Data virtualization retrieves and interprets data, but does not require uniform formatting or a single point of access. Federation is technically a form of data virtualization.

Data Integration


In computinga data warehouse DW or DWHalso known as an enterprise data warehouse EDWis a system used for reporting and data analysisand is considered a core component of business intelligence. They store current and historical data in one single place [2] that are used for creating analytical reports for workers throughout the enterprise. The data stored in the warehouse is uploaded from the operational systems such as marketing or sales. The data may pass through an operational data store and may require data cleansing [2] for additional operations to ensure data quality before it is used in the DW for reporting. Extract, transform, load ETL and extract, load, transform E-LT are the two main approaches used to build a data warehouse system. The typical extract, transform, load ETL -based data warehouse [4] uses stagingdata integrationand access layers to house its key functions. The staging layer or staging database stores raw data extracted from each of the disparate source data systems. The integration layer integrates the disparate data sets by transforming the data from the staging layer often storing this transformed data in an operational data store ODS database. The integrated data are then moved to yet another database, often called the data warehouse database, where the data is arranged into hierarchical groups, often called dimensions, and into facts and aggregate facts. The combination of facts and dimensions is sometimes called a star schema. The access layer helps users retrieve data. The main source of the data is cleansedtransformed, catalogued, and made available for use by managers and other business professionals for data miningonline analytical processingmarket research and decision support. Many references to data warehousing use this broader context. Thus, an expanded definition for data warehousing includes business intelligence toolstools to extract, transform, and load data into the repository, and tools to manage and retrieve metadata. Instead, it maintains a staging area inside the data warehouse itself. In this approach, data gets extracted from heterogeneous source systems and are then directly loaded into the data warehouse, before any transformation occurs. All necessary transformations are then handled inside the data warehouse itself. Finally, the manipulated data gets loaded into target tables in the same data warehouse. A data warehouse maintains a copy of information from the source transaction systems. This architectural complexity provides the opportunity to:. In regards to source systems listed above, R. Kelly Rainer states, "A common source for the data in data warehouses is the company's operational databases, which can be relational databases". Regarding data integration, Rainer states, "It is necessary to extract data from source systems, transform them, and load them into a data mart or warehouse". Rainer discusses storing data in an organization's data warehouse or data marts. Metadata is data about data. Today, the most successful companies are those that can respond quickly and flexibly to market changes and opportunities. A key to this response is the effective and efficient use of data and information by analysts and managers. A data mart is a simple form of a data warehouse that is focused on a single subject or functional areahence they draw data from a limited number of sources such as sales, finance or marketing. Data marts are often built and controlled by a single department within an organization. The sources could be internal operational systems, a central data warehouse, or external data. Given that data marts generally cover only a subset of the data contained in a data warehouse, they are often easier and faster to implement. Types of data marts include dependentindependent, and hybrid data marts. Online analytical processing OLAP is characterized by a relatively low volume of transactions. Queries are often very complex and involve aggregations. For OLAP systems, response time is an effectiveness measure. OLAP databases store aggregated, historical data in multi-dimensional schemas usually star schemas. OLAP systems typically have data latency of a few hours, as opposed to data marts, where latency is expected to be closer to one day. The OLAP approach is used to analyze multidimensional data from multiple sources and perspectives.

Data Integration in Data Mining


As we saw earlier, a data warehouse is a database that stores information from other databases using a common format. That's about as specific as you can get when describing data warehouses. There's no unified definition that dictates what data warehouses are or how designers should build them. As a result, there are several different ways to create data warehouses, and one data warehouse might look and behave very differently from another. In general, queries to a data warehouse take very little time to resolve. That's because the data warehouse has already done the major work of extracting, converting and combining data. The user's side of a data warehouse is called the front endso from a front-end standpoint, data warehousing is an efficient way to get integrated data. From the back-end perspective, it's a different story. Database managers must put a lot of thought into a data warehouse system to make it effective and efficient. Converting the data gathered from different sources into a common format can be particularly difficult. The system requires a consistent approach to describing and encoding the data. The warehouse must have a database large enough to store data gathered from multiple sources. Some data warehouses include an additional step called a data mart. The data warehouse takes over the duties of aggregating data, while the data mart responds to user queries by retrieving and combining the appropriate data from the warehouse. One problem with data warehouses is that the information in them isn't always current. That's because of the way data warehouses work -- they pull information from other databases periodically. If the data in those databases changes between extractions, queries to the data warehouse won't result in the most current and accurate views. If the data in a system rarely changes, this isn't a big deal. For other applications, though, it's problematic. Going back to our example from before with the traffic report and mapyou can see how this would be a problem. While the town's map might not require frequent updates, traffic conditions can change dramatically in a relatively short amount of time. A data warehouse might not extract data very frequently, which means time-sensitive information may not be reliable. For those sort of applications, it's better to take a different data integration approach. Descriptions of data are called metadata. Metadata is useful for naming and defining data as well as describing the relationship of one set of data to other sets. Data integration systems use metadata to locate the information relevant to queries. How to Uninstall Programs in Windows. How does JavaScript work and how can I build simple calculators with it? How C Programming Works. Prev NEXT. Data Warehouses. Related How to Uninstall Programs in Windows.

Data warehouse

Login Now. Data integration is one of the steps of data pre-processing that involves combining data residing in different sources and providing users with a unified view of these data. This approach is called tight coupling since in this approach the data is tightly coupled with the physical repository at the time of query. Higher Agility when a new source system comes or existing source system changes - only the corresponding adapter is created or changed - largely not affecting the other parts of the system. For example, let's imagine that an electronics company is preparing to roll out a new mobile device. The marketing department might want to retrieve customer information from a sales department database and compare it to information from the product department to create a targeted sales list. A good data integration system would let the marketing department view information from both sources in a unified way, leaving out any information that didn't apply to the search. In data mining pre-processes and especially in metadata and data warehouse, we use data transformation in order to convert data from a source data format into destination data. It maps the data elements from the source to the destination and captures any transformation that must occur. EG:The structure of stored data may vary between applications, requiring semantic mapping prior to the transformation process. For instance, two applications might store the same customer credit card information using slightly different structures:. Fill in the missing value manually: this approach is time-consuming and may not be feasible given a large data set with many missing values. Use a global constant to fill in the missing value: Replace all missing attribute values by the same constant. Use the attribute mean to fill in the missing value: Use a particular value to replace the missing value for an attribute. Use the attribute mean for all samples belonging to the same class as the given tuple: replace the missing value with the average value of the attribute for the given tuple. Use the most probable value to fill in the missing value: This may be determined with regression, inference-based tools using a Bayesian formalism, or decision tree induction. And can be smoothened using the following steps:. Regression: Data can be smoothed by fitting the data to a function, such as with regression. Multiple linear regressionis an extension of linear regression, where more than two attributes are involved and the data are fit to a multidimensional surface. If you are looking for answer to specific questions, you can search them here. We'll find the best answer for you. If you are looking for good study material, you can checkout our subjects. Hundreds of important topics are covered in them. Download our mobile app and study on-the-go. You'll get subjects, question papers, their solution, syllabus - All in one app. Login You must be logged in to read the answer. Go ahead and login, it'll take only a minute. Explain Data Integration and Transformation with an example. Follow via messages Follow via email Do not follow. Please log in to add an answer. Next up Read More Questions If you are looking for answer to specific questions, you can search them here. Study Full Subject If you are looking for good study material, you can checkout our subjects.

Data Integration



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