The document discusses the Database Task Group (DBTG) model, which features linked record types organized into owner-member sets to meet varied programming language requirements. It describes the storage schema of databases using a data storage description language (DSDL) and compares the DBTG model with other database models like relational, hierarchical, and network. Key differences highlighted include their structural organization, relationship representations, and ease of data access.

1. DBTG MODEL
RAMKRISHNA BHAGAT
MCA(L)

2. Content ◎ Introduction
◎ Need
◎ Architecture
◎ Comparison 2

3. DBTG Model
Data Base Task Group
1

4. “
The Data Base Task Group of the
Conference on Data Systems
Languages (CODASYL), the
group responsible for
standardization of the
programming language COBOL.
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5. Introduction ◎ The structure consisting of two record types that are linked
together is referred to in the DBTG model as a DBTG set.
◎ In each DBTG set, one record type is designated as the
owner, and the other is designated as the member, of the
set.
◎ Each DBTG set can have any number of set occurrences
(actual instances of linked records).
◎ Since many-to-many links are disallowed, each set
occurrence has precisely one owner, and has zero or more
member records.
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6. Owner Member
Relationship
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7. Example of
DBTG Model
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8. ◎ The DBTG is intended to meet the
requirements of many distinct
programming languages.
◎ The DBTG data manipulation language
consists of a number of commands that
are embedded in a host language.
Need
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9. Architecture Storage Schema
◎ The storage
structure (Internal·
View) of the
database is
described by the
storage schema,
written in a Data
Storage Description
Language (DSDL).
(Internal· View)
Schema
◎ The schema
consists
essentially of
definitions of the
various type of
record in the
database.
( logical record types )
Subschema
◎ A subschema
consists
essentially of a
specification of
which schema
record types the
user is interested
in.
( External view)
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10. Comparison
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Relational
• A database model to
manage data as tuples
grouped into
relations.
• Arrange data in table.
• Represent both “one
to many or many to
many relationship.
• Easier to access data.
• Flexible
Hierarchical
• A structure of data
organized in a tree
like model using
parent, child
relationship.
• Arranges data in a
tree similar structure.
• Represents “one to
many “ relationship
• Difficult to access
data.
• Less Flexible
Network
• A database model that
allows multiple
records to be linked to
the same owner file.
• Organizes data in a
graph structure.
• Represent to “many to
many” relationship.
• Easier to access data.
• Flexible

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