COMP3211 Advanced Databases Dr Nicholas Gibbins nmgecssotonacuk 20152016 Two Questions 2 whats inside a DBMS whats the interface to the DBMS Interfaces DDL vs DML DDL Data ID: 493666
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Slide1
DBMS Architecture
COMP3211 Advanced Databases
Dr
Nicholas Gibbins –
nmg@ecs.soton.ac.uk
2016-2017Slide2
Two Questions:
2
what’s inside a DBMS?
what’s the interface to the DBMS?Slide3
Interfaces: DDL
vs DML
DDL – Data
Definition LanguageCreating tables, indicesManipulating database schemaDML – Data Manipulation LanguageQueriesUpdating table contentsSlide4
DBMS Interfaces
Privileged
Commands
DDL
Statements
database
administrators
Application
Programs
application
programmers
Interactive
Query
casual
usersSlide5
Users
Query
Execution
Stored
Database
Application
Programs
Interactive
Query
Privileged
Commands
DDL
Statements
Stored Data
Manager
Runtime DB
Processor
Precompiler
Query
Optimiser
Query
Compiler
DML
Compiler
DDL
Compiler
System
Catalogue
DBMS ComponentsSlide6
Contains metadata about stored data and schemas:
names and sizes of filesstorage details of filesnames and data types of data items
mappings between schemas
constraintsstatistical informationSystem Catalogue
Stored
Database
Application
Programs
Interactive
Query
Privileged
Commands
DDL
Statements
Stored Data
Manager
Runtime DB
Processor
Precompiler
Query
Optimiser
Query
Compiler
DML
Compiler
DDL
Compiler
System
CatalogueSlide7
Processes schema definitions
Stores schema descriptions in the system catalogue
DDL Compiler
Stored
Database
Application
Programs
Interactive
Query
Privileged
Commands
DDL
Statements
Stored Data
Manager
Runtime DB
Processor
Precompiler
Query
Optimiser
Query
Compiler
DML
Compiler
DDL
Compiler
System
CatalogueSlide8
Parses and validates queries
Compiles queries to internal form (query plan)Passes compiled queries to query o
ptimiser
Query Compiler
Stored
Database
Application
Programs
Interactive
Query
Privileged
Commands
DDL
Statements
Stored Data
Manager
Runtime DB
Processor
Precompiler
Query
Optimiser
Query
Compiler
DML
Compiler
DDL
Compiler
System
CatalogueSlide9
Rearranges and reorders operations within query plan
Eliminates redundanciesIdentifies appropriate algorithms and indexes used to implement operationsConsults
system catalogue
for statistical and other informationGenerates executable code Query Optimiser
Stored
Database
Application
Programs
Interactive
Query
Privileged
Commands
DDL
Statements
Stored Data
Manager
Runtime DB
Processor
Precompiler
Query
Optimiser
Query
Compiler
DML
Compiler
DDL
Compiler
System
CatalogueSlide10
Extracts
DML commands from application programs and sends them to the DML
compiler
Precompiler
Stored
Database
Application
Programs
Interactive
Query
Privileged
Commands
DDL
Statements
Stored Data
Manager
Runtime DB
Processor
Precompiler
Query
Optimiser
Query
Compiler
DML
Compiler
DDL
Compiler
System
CatalogueSlide11
Compiles DML into executable code that can be sent to the
runtime processor
DML Compiler
Stored
Database
Application
Programs
Interactive
Query
Privileged
Commands
DDL
Statements
Stored Data
Manager
Runtime DB
Processor
Precompiler
Query
Optimiser
Query
Compiler
DML
Compiler
DDL
Compiler
System
CatalogueSlide12
Executes privileged commands
Executes query plans from the query optimiserAccesses database through stored data manager
Runtime Database Processor
Stored
Database
Application
Programs
Interactive
Query
Privileged
Commands
DDL
Statements
Stored Data
Manager
Runtime DB
Processor
Precompiler
Query
Optimiser
Query
Compiler
DML
Compiler
DDL
Compiler
System
CatalogueSlide13
Controls
access to information on disc, using basic operating system services
Manages shared buffer pool (available main memory used for transferring data to and from disc)
Stored Data Manager
Stored
Database
Application
Programs
Interactive
Query
Privileged
Commands
DDL
Statements
Stored Data
Manager
Runtime DB
Processor
Precompiler
Query
Optimiser
Query
Compiler
DML
Compiler
DDL
Compiler
System
CatalogueSlide14
Other Component Modules
Loading utility
loads files into DBBackup utility dumps DB to secondary storage (tape, typically)Recovery utility deals with failure using backup informationFile reorganisation utility improves performancePerformance monitoring
provides statistics for DBA to decide whether to reorganiseSlide15
Next Lecture:
Data Storage
15