OLAP Functions
| Values | RunningSum | MovingSum | OLAPSum |
| 1 | 1 (1) | 1 (1) | 3 (1+2) |
| 2 | 3 (1+2) | 3 (1+2) | 6 (1+2+3) |
| 3 | 6 (1+2+3) | 5 (2+3) | 9 (2+3+4) |
| 4 | 10 (1+2+3+4) | 7 (3+4) | 7 (3+4) |
What is OLAP and what is it used for?
- Roll-up. Also known as consolidation, or drill-up, this operation summarizes the data along the dimension.
- Drill-down. This allows analysts to navigate deeper among the dimensions of data, for example drilling down from "time period" to "years" and "months" to chart sales growth for a product.
- Slice. ...
- Dice. ...
- Pivot. ...
What does OLAP stand for?
What is OLAP in data warehousing?
- Relational OLAP (ROLAP) – Star Schema based – …
- Multidimensional OLAP (MOLAP) – Cube based – …
- Hybrid OLAP (HOLAP) –
What kind of OLAP do we really need?
Types of OLAP
- Multi-dimensional OLAP (MOLAP)
- ROLAP, Relational On-Line Analytical Processing
- HOLAP, Hybrid OLAP
- WOLAP
- DOLAP
- SOLAP
What are the advantages of OLAP?
Summary:
- OLAP in data warehouse is a technology that enables analysts to extract and view business data from different points of view.
- At the core of the OLAP concept, is an OLAP Cube.
- Various business applications and other data operations require the use of OLAP Cube.
What is a function in Teradata?
Advertisements. Teradata provides built-in functions which are extensions to SQL. Following are the common built-in functions. Function.
What are analytical functions in Teradata?
Teradata analytic functions compute an aggregate value that is based on a group of rows optionally partitioning among rows based on given partition column. Just like other analytics systems, Teradata analytics functions works on the group of rows and optionally ignores the NULL in the data.
What is Msum in Teradata?
The Moving Sum (MSUM) function provides the moving sum or total on a column's value, based on a defined number of rows. The number of rows is referred to as the query width. Like the CSUM, the MSUM defaults to sorting the results in ascending order.
Is Teradata OLAP or OLTP?
Data in a data warehouse is organized to support analysis rather than to process real-time transactions as in online transaction processing systems (OLTP). Although Teradata is geared towards OLAP and Oracle for OLTP, Oracle can run both OLTP and OLAP databases on the same platform, which Teradata does not support.
What are window functions in SQL?
In SQL, a window function or analytic function is a function which uses values from one or multiple rows to return a value for each row. (This contrasts with an aggregate function, which returns a single value for multiple rows.)
What is OLAP in Teradata?
The OLAP functions are built into the Teradata database to provide data mining capabilities and trend analysis. These functions provide processing not available using the standard aggregation. The OLAP functions give the result of their operation and display the detail data values used in the function.
What is CSUM in Teradata?
The Cumulative Sum (CSUM) function provides a running or cumulative total for a column's numeric value. This allows users to see what is happening with column totals over an ongoing progression.
What is the value of CSUM?
CSUM(1,1) returns the same as ROW_NUMBER() OVER (ORDER BY 1), a sequence starting with 1. But you should never use it like that as ORDER BY 1 within a Windowed Aggregate Function is not the same as the final ORDER BY 1 of a SELECT, it's ordering all rows by the same value 1.
What is an olap cube?
The core of most OLAP systems, the OLAP cube is an array-based multidimensional database that makes it possible to process and analyze multiple data dimensions much more quickly and efficiently than a traditional relational database.
How does slice work in OLAP?
The slice operation creates a sub-cube by selecting a single dimension from the main OLAP cube. For example, you can perform a slice by highlighting all data for the organization's first fiscal or calendar quarter (time dimension).
What is the difference between OLAP and OLTP?
The main difference between OLAP and OLTP is in the name: OLAP is analytical in nature, and OLTP is transactional. OLAP tools are designed for multidimensional analysis of data in a data warehouse, which contains both transactional and historical data. In fact, an OLAP server is typically the middle, analytical tier of a data warehousing solution.
What is a multidimensional OLAP?
OLAP that works directly with a multidimensional OLAP cube is known as multidimensional OLAP, or MOLAP. Again, for most uses, MOLAP is the fastest and most practical type of multidimensional data analysis.
What is pivot function?
The pivot function rotates the current cube view to display a new representation of the data—enabling dynamic multidimensional views of data. The OLAP pivot function is comparable to the pivot table feature in spreadsheet software, such as Microsoft Excel, but while pivot tables in Excel can be challenging, OLAP pivots are relatively easier to use (less expertise is required) and have a faster response time and query performance.
What is roll up in OLAP?
Roll up is the opposite of the drill-down function—it aggregates data on an OLAP cube by moving up in the concept hierarchy or by reducing the number of dimensions. For example, you could move up in the concept hierarchy of the “location” dimension by viewing each country's data, rather than each city.
What is a rolap?
ROLAP, or relational OLAP, is multidimensional data analysis that operates directly on data on relational tables, without first reorganizing the data into a cube. As noted previously, SQL is a perfectly capable tool for multidimensional queries, reporting, and analysis.
Why is OLAP used in Excel?
OLAP databases are designed to speed up the retrieval of data. Because the OLAP server, rather than Microsoft Office Excel, computes the summarized values, less data needs to be sent to Excel when you create or change a report.
What is OLAP database?
Online Analytical Processing (OLAP) is a technology that is used to organize large business databases and support business intelligence. OLAP databases are divided into one or more cubes, and each cube is organized and designed by a cube administrator to fit the way that you retrieve and analyze data so that it is easier to create and use ...
What are the two types of data in OLAP?
OLAP databases contain two basic types of data: measures, which are numeric data, the quantities and averages that you use to make informed business decisions, and dimensions, which are the categories that you use to organize these measures.
Can Excel work with OLAP?
Excel can also work with third-party OLAP products that are compatible with OLE-DB for OLAP. You can display OLAP data only as a PivotTable report or PivotChart report or in a worksheet function converted from a PivotTable report, but not as an external data range.
Can you retrieve data from an OLAP server?
If a database on an OLAP server is available on your network, you can retrieve source data from it directly. If you have an offline cube file that contains OLAP data or a cube definition file, you can connect to that file and retrieve source data from it.
What is OLAP in statistics?
Online Analytical Processing Server (OLAP) is based on the multidimensional data model. It allows managers, and analysts to get an insight of the information through fast, consistent, and interactive access to information. This chapter cover the types of OLAP, operations on OLAP, difference between OLAP, and statistical databases and OLTP.
What is hybrid OLAP?
Hybrid OLAP is a combination of both ROLAP and MOLAP. It offers higher scalability of ROLAP and faster computation of MOLAP. HOLAP servers allows to store the large data volumes of detailed information. The aggregations are stored separately in MOLAP store.
What is a Molap server?
MOLAP uses array-based multidimensional storage engines for multidimensional views of data. With multidimensional data stores, the storage utilization may be low if the data set is sparse. Therefore, many MOLAP server use two levels of data storage representation to handle dense and sparse data sets.
What is pivot operation?
The pivot operation is also known as rotation. It rotates the data axes in view in order to provide an alternative presentation of data. Consider the following diagram that shows the pivot operation.
What is OLAP in business?
OLAP basically means On-Line Analytical Processing which means that it can be used to extract or retrieve data selectively so that it can be analyzed from different viewpoints . It is of great value in Business Intelligence and can be used in the analysis of sales forecasting, financial reporting.
What is Oracle OLAP?
Oracle Database OLAP option: As the name suggests this OLAP tool is used to introduce OLAP in the database environment of Oracle. The main objective that it serves is that it can direct the SQL queries to OLAP cubes which in return will speed up the process.
What is Mondrian OLAP server?
Mondrian OLAP server: It is an open-source OLAP tool and it’s USP is it is written in Java. Another feature of this tool that it supports XML language, SQL and other data sources. Ic Cube: Just like the above OLAP tool, this is also written in Java and it is also an in-memory multidimensional OLAP tool. Infor BI OLAP Server: It is ...
What is OLAP tool?
OLAP tools can be classified as the following : 1. MOLAP. It stands for Multidimensional Online Analytical Processing. It stores data in multidimensional arrays and requires pre-computation and storage of information in the cube. Some of the tools for that are: IBM Cognos: It provides tools for reporting, analysis, monitoring of events and metrics.
Why use OLAP for multidimensional presentation?
The multidimensional presentation using OLAP tools helps in better understanding of relationships which was not present previously. Another popular scenario is the “What if” scenarios of OLAP software. They are made eminently more possible by multidimensional processing of OLAP tools.
What does the R stand for in Rolap?
The ‘R’ in ROLAP stands for Relational. So, the full form of ROLAP becomes Relational Online Analytical Processing. The salient feature of ROLAP is that the data is stored in relational databases. Some of the top ROLAP is as follows:
Is pre-modelling required for OLAP?
Pre-modelling is a must in traditional OLAP tools which is a time-consuming process . Great dependence on IT: In this case, a user is a business person but he should have good knowledge of IT. The traditional OLAP tools require heavy involvement of IT technicians and people who have good business expertise along with IT.
