All Content Flashcards
1
Q
Enterprise Information Systems focus on integration. Which are the 3 types of integration?
A
- Data/Information Integration
- Enterprise Application Integration
- Business-to-business Integration
2
Q
Which is the goal of integration?
A
Provide a homogeneous, integrated view on multiple, distributed, autonomous and heterogeneous systems, components, or data sources.
3
Q
Which are the 3 fundamental challenges of integration?
A
- Distribution
- Autonomy
- Heterogeneity
4
Q
Which are the 2 types of distribution?
A
- Logical
- Physical
5
Q
Which are the 4 types of autonomy?
A
- Design
- Interface
- Access
- Judicial
6
Q
Which are the 2 main approaches to resolve heterogeneity?
A
- When needed
- Enforce by establishing standards
7
Q
Which are the 6 types of heterogeneity?
A
- Technical
- Data Model
- Syntactic
- Structural
- Schematic
- Semantic
8
Q
Which are the 2 architectural approaches to achieve data integration?
A
- Materialized integration: replication, data warehousing
- Virtual integration: federated DBMS, multi-DB systems
9
Q
Which are the 4 characteristics of DDBMS?
A
- Distribution by design
- 4-layer schema architecture
- Tightly couple
- Heterogeneity not an issue
10
Q
Which are the 4 characteristics of FDBMS?
A
- Provides homogeneous and integrated view of data from multiple sources (federated conceptual schema)
- “On-Demand” data integration
- Requires: wrapper/mediator technology, data and schema integration mechanisms
- Distribution is given
- Preserves high degree of autonomy
11
Q
Which are the 2 alternatives for federated schema creation?
A
- bottom-up: schema integration
- top-down: schema design, schema mapping
12
Q
Which are the 5 layers of the Schema Reference Architecture?
A
- external schema
- federated schema
- export schema
- component schema
- local schema
13
Q
Mediator-based IS are a generalization of DDBMS and FDBMS. Which are the 2 main components?
A
- wrappers
- mediator
14
Q
Which are the 4 tasks of wrappers?
A
- encapsulate data source for uniform access
- help overcome heterogeneity of data sources
- support global query evaluation and optimization
15
Q
Which are the 3 main characteristics of Garlic?
A
- Garlic and wrappers cooperator for query processing
- Extensibility
- Wrapper evolution (until provide full support of data source functionality)
16
Q
Which are the 4 wrapper services of Garlic?
A
- modelling data as object collection
- method calls
- query planning
- query execution
17
Q
Garlic optimizer builds query plan using bottom-up approach. Which are the 4 steps?
A
- create plan fragments for single collections
- plan the join processing for local joins
- plan the join processing across multiple sources
- finalize the plan (compensations)
18
Q
Which are the 3 methods that wrappers provide to Garlic work requests?
A
- plan_access( )
- plan_join( )
- plan_bind( )
19
Q
Which are the 4 characteristics of MDBMS?
A
- loosely coupled
- no global schema
- multi-database language
- only location and physical distribution transparency
- data model heterogeneity handled by local data source or multi-db language
20
Q
What is the limitation of SQL to solve most forms of schematic heterogeneity?
A
Views can be used under certain specific circumstances. Otherwise the maintenance is expensive.
21
Q
Which are the 3 characteristics of Schematic Query Languages to deal with schematic heterogeneity?
A
- Transform data to metadata (and v.v.)
- Extend relational model to allow dynamic schemas
- mechanism to access different DBs in a single query
22
Q
Which is the main idea of SchemaSQL?
A
Extended FROM clause: ->, db->, db::rel->, db::rel, db::rel.attr
23
Q
Which are the 2 points of criticism over SchemaSQL?
A
- merge not well-defined for all source relations
- semantics of SELECT differs depending on context
24
Q
Which is the main idead of FIRA/FISQL?
A
Provide federated relational model with additional algebra operators.
25
Which are the 6 new operator of FIRA/FISQL?
- Drop-projection
- Down
- Attribute Dereference
- Generalized Union
- Transpose
- Partition operator
26
Which are the 2 motivations for replication?
- increase availability
| - increase performance
27
Which are the 3 challenges for replication?
- transaction processing
- enforcing consistency
- detecting and resolving conflicts
28
Which are the 2 types of replication?
- eager replication
| - lazy replication
29
Which are the advantages and disadvantages of eager replication?
```
+ guarantees globally serializable execution
+ avoid inconsistencies
- deadlocks
- lack of scalability
- cannot be used if nodes offline
```
30
Which are the advantages and disadvantages of lazy replication?
```
+ minimal update overhead
+ works if nodes offline
- stale data
- conflicting updates may cause inconsistencies
- potential for system delusion
```
31
Which are the 2 ways of bidirectional replication?
- master/slave
| - peer-to-peer
32
Which are the 2 replication methods?
- Target table refresh
| - Change-capture
33
Which are the 4 types changes can be capture for replication?
- continuous
- interval-based
- DB events
- one-time snaptshot
34
Which are the 2 realization approaches for capturing data?
- analyze DB log files
| - use DB triggers
35
Which are the 3 main data that should be captured?
- type of change (insert, update, delete)
- new values and item ID
- (optional) before-image information
36
Which are the 2 ways that captured change-data can be provided?
- staging table at source location
| - message-oriented middleware (message queue)
37
How are replication conflicts detected?
Based on timestamps. Object carry most recent update timestamp. Update carries new value and old object timestamp. Provoke wait situations in eager replication. Reconciliation in lazy replication.
38
Which are the 2 possible ownership of replicas?
- Group
| - Master (results in waits in lazy replication)
39
Which are the 3 approach for replication conflicts reconciliation?
- automatically based on rules
- manually (conflicts table or queue)
- non-transactional schemes (abandon serializability for convergence, tolerate lost updates)
40
What is the main goal of data warehousing?
- materialized integration of data from numerous heterogeneous data sources to enable data analysis
41
Which are the 2 main components of OLAP data?
- Facts
| - Dimensions
42
Which are the 2 ways of implementing OLAP schema in a RDBMS?
- Star structure
| - Snowflake structure
43
Which are the __ components of Data Warehouse Architecture?
- Data warehouse manager
- Monitor
- Extractor
- Transformer
- Loader
- Staging area (DB)
- Main warehouse (DB)
44
Which are the 5 approaches for monitoring and capturing change data in data warehousing?
- log-based
- trigger-based
- using replication middleware
- audit columns
- snapshot differentials
45
Which are 5 examples of transformation performer by the Transformer in data warehousing?
- (de-) normalized schema
- generation of global IDs
- data type conversion
- unit standardization
- derived values
46
What are short-term queues used for?
Load control: store requests in temporary queue to avoid creating new processes.
47
What are persistent queues in TP-Monitors used for?
- End-user control (redelivery of output until user explicitly ack)
- Recoverable data entry
- Multi-transactional requests (single request processed in multiple transactions)
48
Which are the 2 advantages of Asynchronous Transaction Processing?
- optimize for throughput
| - avoid resource contention of single-transaction
49
Which are the 3 advantages of Stratified Transactions over single, global TA?
- early commit of individual strata (less contention, higher throughput)
- reduced observed end user response time (commit of root stratum)
- if all TAs in a stratum execute on same node, there is no network traffic for 2PC and TA-Manager does not need to support external coordinator.
50
Which are the 2 requirements for Stratified Transactions?
- all resources of TA must be recoverable
| - resource managers able to participate in 2PC
51
Which are 3 client variations of Stratified Transactions?
- non-transactional client
- one-way messaging
- multiple clients submitting requests (one reply queue per client)
52
In the case of a non-transactional client in Stratified Transactions, how can the fault-tolerance be implemented?
- guarantee that message is persistently stored when enqueue message operation return to client
- provide message_id about the last request submitted, last reply received when client reconnects after failure
53
Which are the 5 characteristics of Message Queuing Systems?
- evolved from queue systems in TP-monitors
- message-oriented
- loosely-coupled
- provide persistent message queues
- transactional
54
Why are Message Queue Systems loosely coupled?
- client is not blocked during request processing
- server can chose processing time and release resources/locks early
- components do not need to be active at the same time
55
Which are 3 variations of interactions with MQS?
- shared queues (multiple consumers per queue, but particular message has single consumer)
- additional message properties (priority, time-out)
- enhanced flexibility for consumers (beyond FIFO)
56
Which are 2 messaging delivery modes in MQS?
- persistent
| - non-persistent
57
How is the message order in the messaging model of MQS?
Message sent by single session are received in order. Sending order affected by priority. Sending order guaranteed only within same delivery mode. Sending order affected by transaction order of message.
58
How are transactions provied by MQS?
Transactional sessions. Messages are acked at TA commit. Queues recovered automatically at rollback.
59
How does message acknowledgement works in MQS?
Messages have to be acked after received and then they are removed from queue.
60
Which are the 3 ways non-transactional sessions can acknowledge messages in MQS?
- lazy ack
- auto ack (after successful receive)
- client ack (explicit)
61
How do message selectors work in MQS?
Queue based on logical conditions that refers header and properties fields of messages.
62
What is the main idea of Message Routing?
Message router use scripts to separate routing+transformation logic from the applications.
63
Which are the 3 categories in which a subscription can be classified in a Publish/Subscribe system?
- static (deployment) vs. dynamic (run-time)
- type-based vs. parameter-based (boolean condition)
- non-durable vs. durable
64
Which are the 5 main aspects of Message Brokering?
- Message transformations
- Message routing and transport
- Rules-based processing and distribution of message based on message fields
- Message repository
- Message warehouse
65
What is a message repository in Message Brokering used for?
- definition of message structures
- mapping rules
- transformation functions
- routing scripts
- subscription requests
66
Which are the 3 topologies of a Message Broker?
- hub-and-spoke
- multi-hub
- federation
67
Which are the 2 roles of DBMS in a messaging world?
- persistence manager
| - provided advanced DBMS capabilities to achieve synergy (queue messaging data)
68
Which are the 3 dimensions of Workflow?
- what (Business Process)
- who (Organization)
- with (Business Function Implementation)
69
Which are the 3 steps of Business Process Re-Engineering?
1. Discovery
2. Optimization (static)
3. Analysis (instrumentation, analytic simulation, quantitative aspects)
70
What is defined by atomic spheres?
A set of activities where either all activities commit or none.
71
What is defined by compensation spheres?
Set of activities that must complete as a whole or semantically undone. Each activity in the sphere is associated with a compensation action.
72
What is the Phoenix Behavior?
Forward recovery. Workflow is made persistent and recoverable.
73
What is the motivation for Web Services composition?
- Interact with business partners
- New web services out of existing ones
- Composition can be iterated
74
Which are the 3 main elements of a Web Service Composition Middleware?
- composition model and language
- development environment
- run-time environment
75
What is the difference between middleware for composition and coordination of Web Services?
- Composition: focus on implementation of operation in WS. Internal and private. Used to automate execution of composed WS.
- Coordination: focus on conversation protocols. Public and standardized protocols.
76
Which are the 2 types of process that can be defined using BPEL?
- executable process (composition)
| - abstract process (coordination)
77
What is defined by the business process in BPEL?
- execution order of web services
- data shared between web services
- correlation information
- partners involved in business process and their interfaces
- exception handling
78
What is the BPEL Component Model?
Components in BPEL are Web Services described using WSDL.
79
Which are the basic activities in BPEL?
- Invoke (async or sync)
- Receive (wait for message)
- Reply (sync response to receive)
80
Which are the structured activities defined by BPEL?
- Sequence
- Switch
- While / For each
- Pick
- Flow (parallel execution)
81
Which BPEL activities can start a process?
- receive
| - pick
82
Which are the 5 phases of Information Integration?
- Analysis
- Discovery
- Planning
- Deployment
- Run-time
83
Which are the 2 approaches for Information Integration?
- bottom-up (well-known set of schemas)
| - top-down (schemas not know, changes, create based on application requirements)
84
Which are the 3 phases of CUPID?
1. Linguistic matching
2. Structure matching
3. Creation of mappings/matches
85
Which are the 3 phases of CUPID Linguistic Matching?
1. Normalization
2. Categorization
3. Comparation
86
What is the trade-off of CUPID in terms of similarity matches?
- confidence of false positives reduces
| - confidence of false negative increased
87
Which are the 4 properties of an integrated schema?
- complete
- minimal
- correct
- intelligible
