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"Relational DB uses the _________ model: Entities and Relationships are represented by ___________, ___________" relational, relations, tables
What needs to be determined to create a relational model of a real-world enterprise?
- Entities (students/courses)
- Relationships (student taking a course)
- Attributes (ID, name)
Within a table, ROWS represent _______ or _______ records, tuples
Are records unique? Yes
A primary key can be made up of ______ or _______ ______________ one or more attributes
Within a table, each column represents an ___________. Do columns have to be unique? attribute
yes
Table is also considered an instance of a _____________ schema
Where are schemas defined? In the DB
Where is the schema stored? system catalog
Would Schemas be considered a part of the meta data? Yes
Schema is associated with what? One or more constraints
Multiple table queries generally entail what? Joins
or at least similar operation
Can joins be cheap processing? What 'O' algorithm are joins No, they are expensive
~ O(n²)
________ must determine which join algo to use in _____ ______ __________ DBMS any given query
______ facilitates access to DBs DBMS
An application uses a __________ _____ when interacting with a DB. Give examples of how information is related to schemas conceptual view
tables, columns, domains, etc
DBMS maps the ________________ view to the ________ view. conceptual, physical
Data is stored in ________ ________ or ________ _______ while using most efficient access methods, examples being... main memory or secondary storage
indexes
DBMS is responsible for ____________ data from ______ ___________ accessing data from storage devices
Why use a DBMS? To store data for:
- complex data model
- large data set
Additional issues a DBMS can handle are
- Concurrency
- Recovery
- Security
DBMS is linked to application @ compile time (same address space)
Where are embedded DB applications often used? mobile systems
Tiered Client-Server application Application connects to DBMS via ODBC, JDBC, etc
May entail connecting to a server that connects to a DB server
Application and DBMS are considered combined or separate machines. separate
Through what does an Application and DBMS communicate? a network
In a tiered architectures, the different number of tiers can refer to
- client interface
- business logic
- network communication
- ...
Client-Server architecture is common with what type of DBMS? Enterprise DBMSs
Describe DBMS functionality Manages the following:
- Connections
- data manipulation language commands
- commands and generates query plan
- returning of results
What does it mean to manage data manipulation language commands
- ctrl when to process a query
- assigns threads to run commands
What does commands and generates query plan mean?
- Using storage and transaction management code
Thrashing when OS spends more time swapping pages between memory and disk than executing processes.
This happens when the degree of multiprogramming, or the number of processes in memory, exceeds the available memory space
Throughput average # of units actually being processed
Relational Query Processor
- Once accepted by process manager, query has sufficient resources to be evaluated
- checks user authorization
- generates query plan through a Rewriter and Optimizer
- plan is executed by the Plan Executor
Plan Executor Using general-purpose ops (join, sort, select) to make calls to storage manager for data access
Transactional Storage Manager
- Manages all data access and data manipulation
- Key component for OLTP
- Eff ways to read/modify data
- Guarantees data integrity
- Control returned to query processor
How does the Transactional Storage Manager Eff read/modify data indexes, table formats, buffering and careful use of storage media
How does the Transactional Storage Manager guarantee data integrity
- Manages concurrent access
- Allows for recovery from failures and crashes
Connection Manager Ships the generated results back
How do different DBMSs differ
