Abstract

In this (short!) article, I describe the common terms related to data storage that I believe most of the data industry accepts but, generally, does not take sufficient time to pin down. I hope this simple page, despite its brevity, will help you better understand my other articles.

Data storage

Here I define the structure of recorded data (which is fundamental to all we do).

Diagram

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Notes:

1. The data environment contains any number of data stores.

2. A data store contains any number of data assets.

3. A data asset contains any number of data records.

4. A data record contains any number of data attributes.

5. A data value is stored for a given data attribute of a given data record.

6. The terms in parentheses are the relational synonyms.

Relational databases

Databases are defined and implemented differently across RDBMS vendors. But most hue closely to the SQL Standard which dictates that data values are stored in a hierarchical (nested) set of named objects.

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Where:

· A server manages an Instance.

· An instance contains any number of Databases.

· A database contains any number of Schemas.

· A schema contains any number of Tables.

· A table contains any number of Columns.

Any given object can be referenced with a multi-part name following that hierarchy:

· A database is identified by its name as in “database1”.

· A schema is identified, within a named database, by its name as in “schema1.database1”.

· A table is identified, within a named schema, by its name as in “schema1.database1.table1”.

· A column is identified, within a named table, by its name as in “schema1.database1.table1.column1”.

Note: There are shortcuts by which one can omit the higher levels of the name based on the context in which the SQL statement is running.