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dal (dal-1.198) [xmmsas_20211130_0941-20.0.0]

Data Model

The DAL is principally concerned with data organisation and access.

The DAL Data Model organises data into a collection of data sets.

A data set, which, for aesthetic reasons, will be written as the collocation dataset throughout this document, is an attributable set together with an ordered collection of zero or more blocks. Sometimes a dataset is said to be an attributable set or simply attributable.

A block is one of:

An array is an attributable set together with an n-dimensional array (1 « n « 3) of numeric scalars. The scalars all have the same type. Sometimes an array is said to be an attributable set or simply attributable.

A table is an attributable set together with an ordered collection of zero or more columns. Sometimes a table is said to be an attributable set or simply attributable.

A column is an attributable set together with a vector of cells. Sometimes a column is said to be an attributable set or simply attributable. A cell is one of:

A scalar is one of:

A numeric scalar is one of:

The scalars within a particular array or column all have the same type.

An attributable set, which for the purposes of brevity will be shortened to attributable throughout this document, is the quintuple
{ name, label, setofattributes, setofhistoryrecords, setofcommentrecords }
where:

An attribute is a quadruple { name, label, unit, value }, where:

XMM-Newton SOC -- 2021-11-30