What is a fact table what type of data is stored in fact tables?

A fact table is the central table in a star schema of a data warehouse. A fact table stores quantitative information for analysis and is often denormalized.

Why is fact table in normal form?

Basically the fact table consists of the Index keys of the dimension/ook up tables and the measures. so when ever we have the keys in a table . that itself implies that the table is in the normal form.

What is a fact table in data warehouse?

In data warehousing, a fact table consists of the measurements, metrics or facts of a business process. It is located at the center of a star schema or a snowflake schema surrounded by dimension tables. Each record in this fact table is therefore uniquely defined by a day, product and store.

Is fact table a reference table?

Fact table is a measurable event for which dimension table data is collected and is used for analysis and reporting. Collection of reference information about a business. Facts tables could contain information like sales against a set of dimensions like Product and Date.

How do you identify a fact table?

The fact table is usually highly normalized, containing only keys and metrics.

1. Identify Subject Areas.
2. Within each subject area, identify the operational transactions that depict key business events.
3. Identify the major dimensions for each fact table.
4. Look for fact tables that contain both facts and dimensions.

What is difference between fact table and dimension table?

The main difference between fact table or reality table and the Dimension table is that dimension table contains attributes on that measures are taken actually table. 1. Fact table contains the measuring on the attributes of a dimension table.

What is denormalized dimension table?

For dimension tables, you generally model these as one table per object. Building the dimension in the ETL system involves joining the various normalized description and hierarchy tables that populate the dimension attributes and writing the results into a single table.

Is star schema normalized or denormalized?

The snowflake schema is a fully normalized data structure. Dimensional hierarchies (such as city > country > region) are stored in separate dimensional tables. On the other hand, star schema dimensions are denormalized.

What are measures in fact table?

A fact table or a fact entity is a table or entity in a star or snowflake schema that stores measures that measure the business, such as sales, cost of goods, or profit.

What is fact table with example?

A fact table is found at the center of a star schema or snowflake schema surrounded by dimension tables. A fact table consists of facts of a particular business process e.g., sales revenue by month by product. Facts are also known as measurements or metrics. A fact table record captures a measurement or a metric.

How do you identify a fact and dimension table?

A foreign key in a fact table is the primary key of a dimension table. If a table has a composite key then it is a fact table. If a table does not have a composite key then it is a dimension table.

Does fact table have primary key?

The fact table also has a primary (composite) key that is a combination of these four foreign keys.

Are factfact tables completely normalized?

Fact tables are completely normalized. The fact table is in normalized structure as the redundant information is maintained in the dimension tables. The fact table contains foreign keys to the dimension tables.

What is the difference between normalized and denormalized table structures?

Dimensional models combine normalized and denormalized table structures. The dimension tables of descriptive information are highly denormalized with detailed and hierarchical roll-up attributes in the same table. Meanwhile, the fact tables with performance metrics are typically normalized.

What is the difference between a fact table and a dimension table?

Generally it is the schema that is denormalized than just the fact table. Fact table ideally contains the aggregatable numeric values and reference keys to the dimension tables for slicing purposes. In some architectures, fact tables could just look like a few columns with numbers. It is the dimension tables that help you analyze those numbers.

Can I DENORMALIZE a table with snowflaked dimension attributes?

While we advise against a fully normalized with snowflaked dimension attributes in separate tables (creating blizzard-like conditions for the business user), a single denormalized big wide table containing both metrics and descriptions in the same table is also ill-advised.