Re: Help with Terminology (Info, data, value, ...)

"James" <jraustin1_at_hotmail.com> wrote in message news:a6e74506.0206101004.4c21b316_at_posting.google.com...
> What are the distinctions between the words "information", "schema",
> "data", "value", "data type", "field type" and "type" with respect to
> a database?

Abbreviating and paraphrasing from the ISO/IEC 2382 standard vocabularies:

Information: Knowledge that within a certain context has a particular meaning.
Data: A representation of information in a formalized manner suitable for communication, interpretation or processing.

i.e. Information can only be interpreted by humans. Data can be interpreted by either humans or machines.

Schema: Complete description of the structure of a database pertaining to a specific level of consideration.
Database schema: A set of schemas for each of the various levels of consideration.
There are also Internal schema, External schema, Conceptual schema, Conceptual subschema, Logical schema, and Physical schema.

External level: User-oriented representation of information. Internal level: Representation of information within a physical implementation.
Logical level: Data abstract from physical implementation. Physical level: Physical representation of data structures and mappings to storage.

Data type: A set of discrete data units sharing a common representation and operations along with their associated operations. Field type: A data type considered elementary within a given context.

For a few hundred dollars, your company can purchase these documents from ISO/IEC and you will have direct access to the formal definitions.

> Which is the most generic/comprehensive term?
> Which is the least generic/most inclusive term?
> Information.
> Schema.
> Data.
> value.

I would categorize them as follows:

Information is the most generic/comprehensive term. Schema is the least generic/inclusive term.

I ignored value in the above since values are single occurences and are the same occurence regardless of representation. Representation of a value generally makes the difference between data and information.

> Which terms include the schema?

I'm not sure exactly what you mean. Most of the schema is data. External predicates are information, but I am not entirely certain whether these are part of the conceptual schema. I assume they are, though.

> Does a database's information include the schema?

Yes.

> Does a database's data include the schema?

Yes, at least most of the schema.

> Which is most correct?
> A database stores information.
> A database stores data.

A database stores data. An information base stores information.

> Which is most correct?
> A record stores information.
> A record stores data.
> A record stores a set of values.

A record is an occurence of a record type. A record type is a composite data type whose components consist of field types or other record types.

A record stores data.

> Which is most correct?
> A field stores information.
> A field stores data.
> A field stores a value.

The ISO/IEC vocabulary lists "field" as "(data) field".

> Which is most correct?
> A field has a field type.
> A field has a data type.
> A field has a value which has a type.

The standard vocabulary states that a field has a field type.

> Related specifically to oodb, which is most correct?
> An object stores info.
> An object stores data.
> An object stores a value.

Your usage is a little fuzzy. By "object" do you mean an object value or an object variable. From the verb "to store", I assume you mean an object variable, in which case it stores data that represents some value.

> An object's [info|data|value] has a [dataType|valueType|Type].

On object variable's data has a data type (perhaps multiple data types) and represents some value. An object value is data that has a data type (perhaps multiple data types) and represents some value.

> What are images, sound clips, video clips? Info, data, or a value?

They are values. Their representation will determine whether they are information or data.

> TIA
Received on Mon Jun 10 2002 - 22:59:25 CEST