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What have we learnt from CSCI585?

  • Chapter 1
    • Data vs Info
      • Data
        • Have not yet been processed to reveal their meaning to the end user
        • Building blocks of information
        • Generation, storage, and retrieval of data
      • Info
        • Produced by processing raw data to reveal its meaning
        • Requires context
        • Should be accurate, relevant, and timely to enable good decision making
        • Bedrock of knowledge
    • Database
      • End user data
      • meta data
      • DBMS
        • program
        • manage database structure
        • control access data
        • Role
          • data to share
          • between database & user
          • view
          • application request
          • hide db internal complexity
        • Advantage
          • Data integrity and less data inconsistency
          • improve data security/sharing/access/decision maker
          • data quality
    • Type of Database
      • general purpose database
        • variety
      • Discipline specific database
        • focused on specific subject area
      • Operational database
        • Designed to day-to-day ops
      • Analytical database
        • store historical data
          • data warehouse
          • online analytical processing OLAP
            • tool for retrieving processing and modeling for data warehouse
      • Business intelligence
        • capture and process biz data to generate info
      • Unstructured data
        • exist in their original state
      • Structured
        • result from formatting
      • semistructured data
      • Extensible Markup Language XML
    • Database  Evolution
      • Manual File System
      • Computerized File System
        • DP specialist,Track data & produce report
      • File System Redux(Excel)
    • Term
      • Data
      • Field
      • Record
      • File
    • Problem with file system
      • lengthy dev times
      • difficulty of getting quick answer
      • complex system admin
      • lack of security and limited data share
      • extensive programming
    • Structure dependence(exist)&independence(access)
    • Data dependence(access storage change) & independence(is changed without affecting ability to access)
      • Practical significant of data independence is diff between logical and physical format
    • Data redundancy
      • poor data security
      • data inconsistency
      • increased likelihood of data-entry error
      • data anomaly
        • update/insertion/deletion anomalies
    • Data system
      • store data structure and relationship
      • define store and manage all access path and component
      • DBMS Functions
        • data dictionary
        • data storage
        • data transformation and presentation
        • security management
        • multiuser access control
        • backup and recovery
        • data integrity management
        • database access language and api
          • SQL
            • DDL
            • DML
        • database communication interface
      • Disadvantage
        • Increased cost
        • Management complexity
        • Maintaining currency
        • Vendor dependence
        • Frequent upgrade/replacement cycle
  • Chapter 2 Data Models
    • Modeling vs Model
      • Data Modeling
        • create a specific data model for problem domain
      • Data models
        • simple representations of complex real world data structure
      • Model
        • Abstract of real object
    • Entity vs Relationship
      • entity is an object to collect and store data
      • relationship
        • one to many
        • many to many
        • one to one
      • Constraint
    • Business Rules
      • brief precise and unambiguous
      • define the basic building blocks
      • describe main and distinguishing characteristics
    • Hierarchical Model vs Network Model
      • H
        • large amount of data for complex manufacturing project
        • tree which contains segment
        • 1:M
      • N
        • 1:M & M:M
        • represent complex data relationship effectively
        • improve database preformance
        • allow a record to have more than one parent
    • Schema & Subschema
    • Relation or table: matrix composed of intersecting tuple and attribute
      • Tuple: Row
      • Attribute: Column
    • RDBMS
      • H&N DBMS
      • relational model
      • ERD
        • use graphic to model database component
      • Connectivity
        • label relationship types
      • Entity instance
        • Row in the relational table
      • Graph
        • Chen Notation
        • Crow’s Foot Notation
        • UML
    • OODBMS
      • object-oriented
      • abstraction of real world entity
      • Attributes
        • Describe properties of an object
      • Class
        • collection of similar objects
          • class hierarchy(each class has only one parent)
        • Inheritance
          • inherit methods and attributes of parent
        • UML
    • ERDM & XML
      • Extended relation data model
        • support OO
        • Object and relational dbms
      • XML
        • unstructured data for efficient and efficient exchange of all data type.
    • Big data
      • find new better way to manage large amount of web and sensor-generated data
      • provide high performance and scalability at a reasonable cost
      • Volumne
      • Velocity
      • Variety
    • Hadoop\HDFS\MapReduce\NoSQL
    • NoSQL
      • distributed database architecture
      • provide high scalability high availability and fault tolerance
      • large amount of sparse data
      • gear toward performance rather than transaction consistency
      • key-value store
    • Evolution of data models
      • Hierarchy Model
        • Pros
          • Promote data sharing
          • Parent/child relationship promote
          • database security is provided
          • 1:M efficient
        • Cons
          • physical data storage
          • navigational system require knowledge of h path
          • change in structure require change in all application programs
          • implementation limitaion
          • no data definition
          • lack of standards
      • Network Model
        • Pros
          • Conceptual simplicity
          • Handle more relationship types
          • Data access is flexible
          • data owner
          • conformance to standard
          • DDL DML
        • Cons
          • System complexity limit
          • navigational system yield complex implementation
          • structural changes require changes in all application
      • Relational Model
        • Pros
          • Structural independence
          • Tabular view
          • ad hoc query based on sql
          • isolates the end user from
          • improves implementaton
        • Cons
          • require substantial hardware
          • conceptual simplicity give untrained people the tools to use a good system poorly
          • may promote info problems
      • Entity Relationship Model
        • Visual modeling yield conceptual simplicity
        • Visual representation makes it an effective communication tool
        • Is integrated with the dominant relational model
        • Cons
          • Limited constraint
          • Limited relationship
          • No data manipulation language
          • loss of info content occurs when attribute removed
      • OOM
        • Semantic content is added
        • Visual representation includes semantic content
        • Inheritance promotes data integrity
        • Cons
          • Slow development of standards caused vendor to supply their own enhancement
          • complex nav system
          • learning curve is steep
          • high system overhead slow transactions
      • No SQL
        • High scalalility, avalibility
        • Use low-cost commodity hardware
        • support big data
        • k-v
        • Cons
          • complex programming is required
          • no relationship support
          • no transaction integrity support
          • data consistency eventually consistent model
    • Models level
      • External schema(abstraction high)(user view)
        • specific representation of an external view
        • Text
      • Conceptual schema(ER diagram)
        • high level description of the main data objects
        • logical design task of creating a cs
        • Tables
      • Internal schema (sql, specific database)
        • use database construct supported by the chosen database
        • logical independence
        • (sql)
      • physical model (storage)
  • Chapter 3 Relation Database Model
    • Logical view of data
      • facilitated by the creation of data relationships based on a logical construct called a relation
    • Keys
      • Primary Key
      • Dependencies
        • Functional Dependence( value of one or more attr determine other)
          • Determinant attribute who determine
          • Dependent
        • Full functional Dependence
          • Entire collection of attributes in determinant
      • Composite Key (AreaNo. Phone)
      • Key attribute
      • Entity integrity
        • PK unique
        • PK is not null, even part of it
      • Referential integrity
        • null
        • or primary key in a table
      • Secondary key
        • key used strictly for data retrieval purpose
      • Relvar
        • variable holds a relation
          • heading contain the names of the attribute and the body contains the relation
        • Closure
          • embed
      • Relational Set Op
        • select
        • project
        • union
        • intersect
        • difference
          • yield all row not in the other table
          • union campatible
        • product
          • A table * B table
        • join
          • with a foreign key, common attribute
          • natural Join
          • equiljoin
          • thetajoin
          • inner join(only return matched from table being joined)
          • outer join(match pairs retain and unmatched)
            • right outer right weizhong
            • left outer left weizhong
        • divide
          • 2 column/1 column
          • output is 1 column that contain all values from the second column of the dividend that associated with every row in the divisor.
          • A(a, b)/B(b’)
            • = C(a’), a’ only has a’s b include all b’
        • Data dictionary
        • System catalog
    • Relationships
      • 1:M
      • 1:1
      • M:N
      • Composite entity, bridge entity, associate entity
        • show in
        • register
        • has
      • redundancy
        • serve crucial info purpose
        • preserve the historical accuracy of the data
    • Indexes
      • Index Key
        • index reference point that lead to data location identified by the key
      • Unique Index
        • index key can have only one pointer value associated with it
      • Each index is associated with only one table
    • Dr Codd’12 rules
      • infomation
      • guaranteed access
      • systematic treatment of nulls
      • dynamic online catalog based on the relational model
      • comprehensive data sub lang
      • view update
      • high level insert update delete
      • physical data independence
      • logical data independence
      • integrity independence
      • distribution independence
      • nonsubversion
      • rule zero
        • a database must use its relational facilities exclusively for management
  • Chapter 4 ER Modeling
    • ERD & ERM
    • Attribute
      • Optional attribute can be null
      • required attribute can not be empty
    • Domain possible value
    • Identifiers one or more attr uniquely identify each entity instance
    • Attributes
      • Composite identifier
      • Composite attribute
      • simple attribute
      • single valued attribute
      • multivalued attribute
        • deprived attribute
    • Relationship
      • Both direction
        • Participant
        • Connectivity
        • Cardinality
          • min or max number of entity occurence
      • Weak & Strong
        • weak (non-identifying)
          • primary key of related entity not contain primary key component of parent entity
          • Condition
            • existence-dependent
          • Database designer determine whether or not based on business rules
          • dot line
        • strong (identifying relationship)
          • contain
          • solid line
      • Participation
        • optional participation
          • o-|
          • 0≡
        • mandatory participation
          • |≡
          • ||
      • Relationship  Degree
        • Unary relationship
          • within a single entity
          • Recursive relationship
        • Binary relationship
          • two entities are associated
        • Ternary relationship
          • Three entities are associated
      • Database design challenges
        • must conform to design standard
        • need for high processing speed may limit the number and complexity of logically desirable relationship
        • need for maximum info generation may lead to loss of clean design structure and high transaction speed
  • Chapter 5 Advance data modeling
    • EERD
      • extended entity relationship model
    • Entity supertypes and subtypes
      • supertype
        • common characteristics
      • subtype
        • unique characteristics of each entity subtype
      • Specialization Hierarchy (Employee ->(engineer, manager, designer))
        • depicts arrangement of higher-level entity supertype and low-level entity subtype
        • is-a relationship
        • subtype exists within the context of a supertype
        • every subtype has one supertype to which it’s directly related
        • supertype can have many subtypes
      • Inheritance
        • enable an entity subtype to inherit attribute and relationship of supertype
        • inherit primary key
        • 1:1 super:sub
        • inherit all relationship
        • lower-level subtype inherit all attribute
      • Subtype discriminator
        • controller
      • disjoint and overlapping
        • disjoint subtypes
          • subset of supertype entity set
          • nonoverlapping subset
        • overlapping subset
          • nonunique
      • Completeness Constrain
        • partial
        • total completeness
          • every subtype must be a member of any
      • Specialization and Generalization
        • specialization
          • top-down process
        • generalization
          • bottom up
    • Entity Cluster
      • Virtual entity type
    • Primary Key
      • non inteligent
      • no change over time
      • preferable single-attribue
      • preferable numeric
      • security compliant
    • Composite Primary Key
    • Surrogate Primary Key
    • Time-variant data
    • Fan Trap
    • Redundant relationship
  • Chapter 7 Normalization
    • 1NF
      • Table format
      • No repeating groups
      • PK identified
    • 2NF
      • 1NF
      • no partial dependencies
        • determinant is only part of pk
    • 3NF
      • 2NF and no transitive dependencies
    • 4NF & BCNF
      • BCNF
        • every determinant is a candidate key
      • 4NF
        • 3NF and no independent multivalued dependencies
    • Partial dependency
      • functional dependence in which the determinant is only part of pk
    • Transitive dependency
      • an attribute functionally depends on another nonkey attribute
    • Functional dependence
      • each value determine one and only one value of B
    • Repeating group
      • group of multiple entries of same type can exist for any single key
    • All relational table satisfy 1NF requirement
    • Improving the Design
      • atomic attribute
        • further divided
        • atomicity
      • granularity
        • level of detail represented by the value store in row
    • Surrogate Key
      • numeric value auto_incremented
    • Denormalization
      • creation of normalized relations
      • processing requirements and speed
      • Joining a large number of table
      • Defects
        • less efficient
        • indexing is more cumbersome
      • Case
        • redundant data
        • derived data
        • preaggregated data
        • information requirements
  • Chapter 8 SQL
    • Check
      • create table with default maybe. check(xx in (‘s’,’d’))
    • create view/drop view
    • create index
      • create index p_indx on table(column)
      • create unique index name_index on table(column, column)
    • Constraint constraint_name unique(xx,xx)
    • Special
      • Between
      • is null
      • like
        • %
        • _
      • in
      • exist
    • alter table
    • Group
      • group by
      • order by
      • having
  • Chapter 8 Advance SQL
    • JOIN
      • cross join
        • select * form T1,T2;
      • inner join
        • select * from T1,T2 where T1.C1 = T2.C1;
        • select * from T1 natural join T2;
        • select * from T1 JOIN T2 Using (C1);
        • select * from T1 JOIN T2 ON (T1.C1=T2.C1);
      • outer join
        • select * from T1 left outer join T2 on t1.c1=t2.c1;
        • select * from T1 right outer join T2 on t1.c1=t2.c1;
        • select * from T1 full outer join T2 on t1.c1=t2.c1;
    • Operator
      • IN
      • ALL
      • ANY
      • EXISTS
      • EXCEPT
      • MINUS
      • UNION
      • INTERSECT
    • VIEW
      • create view view_name as select query
  • Chapter 10 Transaction Management & Concurrency Control
    • Transaction
      • Logical unit of work that must be entirely completed or aborted
      • Consistent database state
        • Data request = 1 sql
      • Properties
        • Atomicity
          • must be completed
          • if not, transaction is aborted
        • Consistency
        • Isolation
          • data used in first transaction cannot be used in second
        • Durability
          • once transaction is commited
          • can not be undone or lost
        • Serializability
          • consistent result
      • Transaction will end when
        • commit
        • rollback
        • end of program is reached
        • program is abnormally terminated
      • Log
        • keep track of all transaction
        • use for
          • rollback
          • abnormal termination
          • system failure
      • Log Table
        • TRL_ID  Transaction Log Record ID
        • TRX_NUM Transaction Number
        • PRT Pointer to a transaction record id
    • Concurrency Control
      • simultaneous transaction
      • ensure the serializability of transaction
      • Problems
        • lost update
        • uncommitted data
        • Inconsistent retrievals
    • Lock
      • or scheduler
      • Lock method
        • Pessimistic locking
          • confliction is likely
        • Lock manager
          • responsible for assigning and policing the locks
        • Level Granularity
          • database-level
          • table
          • page-level
          • row-level
          • field-level
        • Type
          • binary lock
          • exclusive lock
            • exists when access is reserved for transaction that locked the object
          • shared lock
            • exists when concurrent transaction are granted read access on the basis of a common lock
        • Deadlocks
      • To-Phase Locking 2pL
        • not prevent deadlock
        • Growing phase
          • acquire
        • Shrinking phase
          • release without obtain new lock
        • Governing rules
          • two transaction can not have conflicting locks
          • no unlock operation can precede a lock operation in the same transation
          • no data are affected until all locks are obtained
        • deadly embrace
          • prevention
          • detection
          • avoidance
        • Time stamping
          • uniqueness
          • monotonictiy
            • always increase
      • Optimistic Method
        • majority of op don’t conflict
        • without restriction
        • phase
          • read
            • read uncommited
              • only allow phantom reads and non-repeatable read
            • read commited
              • do not allow dirty read
            • repeatable read
            • serializable
              • all not allowed
          • validation
            • will not infect the integrity of consistency of database
          • write
      • Data recovery
        • restore database from a given state
        • atomic transaction property
        • Concepts
          • Write ahead log protocol
            • logs are always written before data are updated
          • Redundant transaction log
            • physical disk failure
          • Buffers
            • temporary storage area in primary memory
          • checkpoints
            • allow dbms to write all its updated buffer from mem to disk
        • Write-procedure
          • deferred write & deferred update
            • only transaction log is updated
          • write-through
            • database is updated by transaction operation during transaction’s executed
  • Chapter 11 Data Performance Tuning and Query Optimization
    • Database performance tuning
    • DBMS performance tuning
      • response client’s request
    • SQL performance tuning
      • generate SQL query return correct answer in least amount of time
    • DBMS architecture
      • data files
      • extends
      • table space file group
      • data cache
      • SQL cache or procedure cache
    • Database query optimization
      • timing
        • static
          • compiled by dbms
        • dynamic
      • Query processin
        • parsing
        • execution
        • fetching
      • SQL Parsing phase
        • broken down into small units
        • Query optimizer
          • find most efficient way to access data
        • Access plans
          • dbms-specific and translate sql into complex I/O operation
          • if access plan exists in sql cache
            • resue it
        • SQL execution
          • I/O operations
          • locks are acquired
          • data are retrieved and placed in data cache
        • SQL Fetching Phase
          • DBMS use temp table space to store temp data
          • movement of result set rows from server cache to client cache
        • Bottleneck
          • IO
      • Index and Query optimization
        • Index
          • help speed up data access
          • facilitate searching sorting and using aggregate function joint operation
          • ordered set of value that contain the index key and pointers
          • more efficient than a full table scan
        • Data sparsity
          • number of diff values a column could have
            • hash indexes
            • B-tree
            • Bitmap
          • DBMS determine best type of index to use
        • Choices
          • Rule-based opt
          • Cost-based opt
        • affect optimizer
          • make decision base on existing statistics, which might be old
          • might choose less-efficient decisions
          • Optimizer hints
            • special instruction for optimizer
            • embedded in sql
              • ALL_ROWS
                • select /*+ ALL_ROWS */* from table;
                • minimize the overall exe time
                • batch mode processes
              • FIRST_ROW
                • select /*+FIRST_ROW */* from table;
                • minimize the time needed to process the first set of rows
                  • minimize the time needed to return only the first set
                  • interactive mode processes
              • INDEX(name)
                • select /*+ INDEX(P_QOH_NDX) */* from product;
                • force the optimizer to use P_QOH_NDX index to process this query
        • SQL Performance
          • most dbms automatic query opt at the server end
          • most sql performance opt techniques are dbms-specific and thus rarely portable
          • mainly because poorly written SQL`
        • Index
          • function-based index
            • based on specific sql funtion
          • indexes can not always be used to improve
          • Conditional expression
            • expressed with where or having clause
            • use simple columns or literals as operands
              • numeric field comparisons are faster than character date and null comparison
            • equality comparison are faster than inequality
            • transform conditional exp to use literal
            • write equality condition first when using multiple conditional exp
            • when using AND conditions, write the condition most likely to be false first
            • OR, true first
            • Avoid the use of NOT
          • Query formulation
            • identify what columns and computations are required
            • identify source tables
            • determine how to join table
            • determine selection criteria
            • order to display
          • DBMS Tuning
            • Data cache
              • SQL cache
              • Sort cache
              • optimizer mode
            • in-memory database
            • store large portion
            • Physical
              • RAID to provide a balance between performance improvement and fault tolerance
              • disk contention
              • high usage table in own table space
              • assign separate data files in separate storage volumes for indexes, system and high-usage table
            • index organized table
            • clustered index table
          • store computed and aggregate attribute in table
  • Chapter 12 Distributed Database Management
    • DDBMS
      • data and processing function are distributed among several sites
    • Centralized dbms
    • in biz environment
      • Rapid ad hoc data access
      • distributed data access
      • mobile/internet/application as a service/big data
    • Distributed processing
      • logical processing is shared among two or more physical independent sites via network
    • Distributed database
      • store logically related database over two or more physically independent sites via network
    • DDBMS component
      • Computer workstation
      • network hardware
      • communication media
      • Transaction processor
        • TM
        • AP
      • Data processor DP
        • aka DM
      • Each TP can access data on any DP, and each DP handle all requests for local data from any TP
    • Single-Site Processing, single site data SPSD
      • processing is done on a single host
      • data store on host
      • processing restricted on end user side
      • DBMS is accessed by dumb termials
      • Centralized
    • MPSD
      • shared a single data repo
      • accessed through LA
      • CS architecture
    • MPMD
      • homogeneous
        • integrate multiple instance of same dbms over a network
      • heterogeneous
        • different type of dbms over
      • fully heterogeneous
        • different dbms and different data model
    • Distributed transparency
      • distribution transparency
        • Fragmentation location and local mapping
        • unique fragment
        • Distributed data dictionary DDD
        • distributed global schema
      • transaction
        • will maintain integrity and consistency
        • completed
        • require complex mechanisms to manage transaction
        • distributed request
          • remote request
            • single sql statement access
          • remote transaction
            • single remote site composed of several requests
          • distributed transaction
            • request data from several diff remote site on network
          • distributed request
            • single sql reference data at several DP site
          • 2Phase commit protocol 2PC
            • if a portion of a transaction op cannot be committed, all changes made at the other sites will be undone
            • require that DP’s transaction log entry be written before database fragment is updated
            • Do-undo-redo protocol
              • roll back
              • forward with the help of log
            • Write ahead protocol
              • log before exe
            • Define operation between coordinator and subordinates
            • Preparation
            • final commit
      • failure
        • ensure system will operate in case of network failure
        • minimize total cost
        • replica
        • network latency
        • network partitioning
      • performance
      • Heterogeneity
    • Data fragmentation
      • horizontal fragmentation
        • division of a relation into fragments of rows
      • vertical fragmentation
        • columns
      • mixed fragmentation
        • combine
    • Data allocation
      • centralized data allocation
      • partitioned data allocation
      • replicated data allocation
    • The CAP Theorem
      • consistency
      • availability
      • partition tolerance
      • trade off between consistency and availability is basically available, soft state, eventually consistent
        • propagate
  • Chapter 13 Business Intelligence and Data warehouse
    • OLAP
    • Rollup
    • drilldown
    • CUBE
    • Star schema
  • Chapter 15 Database Connectivity and Web Technology
    • Database middleware
    • UDA
    • ODBC
    • mysqli
    • DAO
    • RDO
    • PDO
    • XML/XSLT
    • DTD
  • Chapter 16 Database Administration and Security
    • Decision Making Cycle
      • data->info->knowledge->decision making->action->data
    • Top of management level
      • strategic decision making
    • middle management
      • deliver the data requirement
    • operation level
    • Information system IS
      • application dev
      • database operation
    • place of DBA
      • higher than db op and app dev
    •  DBA’s function
      • planning
      • design
      • implementation
      • operation
      • training
      • DSO
      • Disaster management
        • full backup
        • incremental backup
        • concurrent backup
    • Security
      • confidentiality
      • compliance
      • integrity
      • availability
      • Identifies security vulnerabilities
      • Identifies measures to protect the system
        • security threat
        • security breach
      • Authorization
        • audit log
    • Data dictionary
      • type
        • integrated
        • standalone 3rd party
      • active data dictionary
      • passive data dictionary
      • Store description of all objects that interact with the database
      • Metadata is the basis for monitoring database use and for assigning access rights to users
      • DBA uses data dictionary to support data analysis and design
    • CASE tool
      • Workbench
    • Type of table space
      • system
      • users
      • temp
      • undotbs
        • recovery info
    • Initialization Parameters
      • trusted_log_flag

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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