# Data Record Collection

A data record collection is an data item set composed of data records.

**Context:**- It can range from being a Structured Data Record Collection to being a Data Record Set without Metadata.
- It can (typically) be a Data Record Multiset (that allows duplicate records).
- It can range from being a Small Data Record Collection to being a Large Data Record Collection.
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**Example(s):**- a Binary Data Record Set, composed of Binary Tuples.
- a Real-Valued Data Record Set, composed of Vector Records.
- a Categorical Data Record Set, composed of Data Tuples.
- A Relational Database Table (a Tabular Record Set).
- A CSV file.
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**Counter-Example(s):**- a Data Record List such as a Time Series Data Sequence.
- a Real-World Entity Set.

**See:**Relational Database, Ground Fact.

## References

### 2011

- (Wikipedia - Data Set, 2011) ⇒ http://en.wikipedia.org/wiki/Data_set
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**data set**(or dataset) is a collection of data, usually presented in tabular form. Each column represents a particular variable. Each row corresponds to a given member of the data set in question. Its values for each of the variables, such as height and weight of an object or values of random numbers. Each value is known as a datum. The data set may comprise data for one or more members, corresponding to the number of rows. … A data set has several characteristics which define its structure and properties. These include the number and types of the attributes or variables and the various statistical measures which may be applied to them such as standard deviation and kurtosis. In the simplest case, there is only one variable, and then the data set consists of a single column of values, often represented as a list. In spite of the name, such a univariate data set is not a set in the usual mathematical sense, since a given value may occur multiple times. Normally the order does not matter, and then the collection of values may be considered to be a multiset rather than an (ordered) list. The values may be numbers, such as real numbers or integers, for example representing a person's height in centimeters, but may also be nominal data (i.e., not consisting of numerical values), for example representing a person's ethnicity. More generally, values may be of any of the kinds described as a level of measurement. For each variable, the values will normally all be of the same kind. However, there may also be “missing values", which need to be indicated in some way. In statistics data sets usually come from actual observations obtained by sampling a statistical population, and each row corresponds to the observations on one element of that population. Data sets may further be generated by algorithms for the purpose of testing certain kinds of software. Some modern statistical analysis software such as PSPP still present their data in the classical data set fashion.

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### 1998

- (Kohavi & Provost, 1998) ⇒ Ron Kohavi, and Foster Provost. (1998). “Glossary of Terms.” In: Machine Leanring 30(2-3).
- Data Set: A schema and a set of instances matching the schema. Generally, no ordering on instances is assumed. Most machine learning work uses a single fixed-format table.