It is represented by a rectangle with rounded edges. Transitions: depicted by arrow from the source state to destination state. Final State: Depicts the end of the. What are the elements in State Chart diagrams? Initial State: This state shows the first activity of the flow. State: A state represents the state of an object at a particular given point of time. Transition: The transition from one state to another state of objects is represented by an arrow. Event and Action: A trigger that causes a transition to occur.
Signal: When a message or a trigger caused by an event to a state, which causes a transition, this message is called as a signal. Final State: The state diagram ends with a diagram that depicts a bull? What are the parts of a deployment diagram? Nodes: A node represents any hardware component. The configuration of hardware is represented by attributes of nodes. Components: A component represents software. Each component straightly represents a class or object that in turn represents methods.
Dependencies: The reliability of one component with that of another is depicted by dependencies. Links: To tie up tow nodes, the links are utilized. The links are implemented by using nodes and their associations. What are the various components in sequence diagrams?
Object: Object is represented by one of components of the system. Unit: A unit is a subsystem, or a sub component or other entity within the system. Separator: Separator represents a boundary among sub systems, components or units. Group: Represents different header elements in the subsystem. UML Interview Questions What are the advantages of using UML? Advantages of using UML breaks the complex system into discrete pieces that can be understood easily.
Handover the system to new team becomes easier. Complex system can be understood by the disparate developers who are working on different platforms. UML model is not a system or platform specific. It unifies all disparate developers under one roof. Supporting Workflows are configuration, change management, and project management. What are the different views in UML? Use Case view — Presents the requirements of a system. Process View — Modeling the systems processes and threads.
Implementation view — Addressing the physical implementation of the system. Deployment view — Model the components required for deploying the system. Define modeling in UML and it advantages. Model is a simplification of reality.
Blueprint of the actual system. Specify the structural and behavior of the system. Templates for designing the system. Helps document the system. What are UML Messages? Specification of a communication What are the three types of modeling in UML? Structural, behavioral, architectural What is UML? Graphical language for visualizing artifacts of the system. Allow to create a blue print of all the aspects of the system.
Some of the benefits offered by iterative development are as follows: — Mitigation of risks in an earlier stage Visibility of progress Feedback, adaptation and engagement. Complexity management Iteration management can improve the overall process of the project because it details and explains the various steps present in it. Supporting Workflows are configuration, change management, andproject management.
Posted on by Leave a comment. Thus the view can insulate users from the effects of restructuring and growth in the database. Hence accounts for logical data independence. What is Data Model? A collection of conceptual tools for describing data, data relationships data semantics and constraints.
What is E-R model? This data model is based on real world that consists of basic objects called entities and of relationship among these objects. Entities are described in a database by a set of attributes. What is Object Oriented model?
This model is based on collection of objects. An object contains values stored in instance variables with in the object. An object also contains bodies of code that operate on the object. These bodies of code are called methods. Objects that contain same types of values and the same methods are grouped together into classes. What is an Entity? What is an Entity type? It is a collection set of entities that have same attributes.
What is an Entity set? It is a collection of all entities of particular entity type in the database. What is an Extension of entity type? The collections of entities of a particular entity type are grouped together into an entity set. What is Weak Entity set? An entity set may not have sufficient attributes to form a primary key, and its primary key compromises of its partial key and primary key of its parent entity, then it is said to be Weak Entity set. What is an attribute?
It is a particular property, which describes the entity. What is a Relation Schema and a Relation? A relation is defined as a set of tuples.
Let r be the relation which contains set tuples t1, t2, t3, …, tn. What is degree of a Relation? It is the number of attribute of its relation schema. What is Relationship? It is an association among two or more entities. What is Relationship set? The collection or set of similar relationships.
What is Relationship type? Relationship type defines a set of associations or a relationship set among a given set of entity types. What is degree of Relationship type? It is the number of entity type participating.
A data base schema is specifies by a set of definitions expressed by a special language called DDL. It specifies user views and their mappings to the conceptual schema. This language is to specify the internal schema. This language may specify the mapping between two schemas.
What is Data Storage — Definition Language? The storage structures and access methods used by database system are specified by a set of definition in a special type of DDL called data storage-definition language. This language that enable user to access or manipulate data as organised by appropriate data model.
What is DML Compiler? It translates DML statements in a query language into low-level instruction that the query evaluation engine can understand. What is Query evaluation engine? It executes low-level instruction generated by compiler. What is DDL Interpreter? It interprets DDL statements and record them in tables containing metadata. What is Record-at-a-time? This retrieve of a record is said to be Record-at-a-time.
What is Set-at-a-time or Set-oriented? This retrieve of a record is said to be Set-at-a-time or Set-oriented. What is Relational Algebra?
It is procedural query language. It consists of a set of operations that take one or two relations as input and produce a new relation. What is Relational Calculus? It is an applied predicate calculus specifically tailored for relational databases proposed by E. How does Tuple-oriented relational calculus differ from domain-oriented relational calculus? The tuple-oriented calculus uses a tuple variables i. QUEL 2. The domain-oriented calculus has domain variables i.
What is normalization? It is a process of analysing the given relation schemas based on their Functional Dependencies FDs and primary key to achieve the properties 1. Minimizing redundancy, 2. Minimizing insertion, deletion and update anomalies. What is Functional Dependency? A Functional dependency is denoted by X Y between two sets of attributes X and Y that are subsets of R specifies a constraint on the possible tuple that can form a relation state r of R.
This means the value of X component of a tuple uniquely determines the value of component Y. What is Lossless join property? It guarantees that the spurious tuple generation does not occur with respect to relation schemas after decomposition.
What is 1 NF Normal Form? The domain of attribute must include only atomic simple, indivisible values. What is Fully Functional dependency? It is based on concept of full functional dependency. A functional dependency X Y is full functional dependency if removal of any attribute A from X means that the dependency does not hold any more.
What is 2NF? What is 3NF? X is a Super-key of R. A is a prime attribute of R. In other words, if every non prime attribute is non-transitively dependent on primary key. Define Entity Set. Compilation of all entries of any particular type of entry in the database is called Entity Set. What do you mean by Entity type extension? Compilation of similar entity types into one particular type which is grouped together as an entity set. What is 4NF? What is 5NF? What is Domain-Key Normal Form? A relation is said to be in DKNF if all constraints and dependencies that should hold on the the constraint can be enforced by simply enforcing the domain constraint and key constraint on the relation.
What is indexing and what are the different kinds of indexing? Indexing is a technique for determining how quickly specific data can be found. What is system catalog or catalog relation?
How is better known as? A RDBMS maintains a description of all the data that it contains, information about every relation and index that it contains. This information is stored in a collection of relations maintained by the system called metadata. It is also called data dictionary. What is meant by query optimization? The phase that identifies an efficient execution plan for evaluating a query that has the least estimated cost is referred to as query optimization.
What is durability in DBMS? Once the DBMS informs the user that a transaction has successfully completed, its effects should persist even if the system crashes before all its changes are reflected on disk.
This property is called durability. What is a Phantom Deadlock? In distributed deadlock detection, the delay in propagating local information might cause the deadlock detection algorithms to identify deadlocks that do not really exist. Such situations are called phantom deadlocks and they lead to unnecessary aborts. What is a checkpoint and When does it occur? By taking checkpoints, the DBMS can reduce the amount of work to be done during restart in the event of subsequent crashes. What do you mean by flat file database?
It is a database in which there are no programs or user access languages. It has no cross-file capabilities but is user-friendly and provides user-interface management. It is one, which keeps its Physical Structure hidden from user. Brief theory of Network, Hierarchical schemas and their properties Network schema uses a graph data structure to organize records example for such a database management system is CTCG while a hierarchical schema uses a tree data structure example for such a system is IMS.
What is a query? A query with respect to DBMS relates to user commands that are used to interact with a data base. The query language can be classified into data definition language and data manipulation language.
What do you mean by Correlated subquery? Subqueries , or nested queries, are used to bring back a set of rows to be used by the parent query. Depending on how the subquery is written, it can be executed once for the parent query or it can be executed once for each row returned by the parent query. If the subquery is executed for each row of the parent, this is called a correlated subquery.
A correlated subquery can be easily identified if it contains any references to the parent subquery columns in its WHERE clause. Columns from the subquery cannot be referenced anywhere else in the parent query. The following example demonstrates a non-correlated subquery. What are the primitive operations common to all record management systems? Addition, deletion and modification. What are the unary operations in Relational Algebra?
JOIN: Concatenation of rows from one relation and related rows from another. Two important pieces of RDBMS architecture are the kernel, which is the software, and the data dictionary, which consists of the system-level data structures used by the kernel to manage the database You might think of an RDBMS as an operating system or set of subsystems , designed specifically for controlling data access; its primary functions are storing, retrieving, and securing data.
An RDBMS maintains its own list of authorized users and their associated privileges; manages memory caches and paging; controls locking for concurrent resource usage; dispatches and schedules user requests; and manages space usage within its table-space structures. How Data dictionary is a set of tables and database objects that is stored in a special area of the database and maintained exclusively by the kernel. What is the job of the information stored in data-dictionary?
The information in the data dictionary validates the existence of the objects, provides access to them, and maps the actual physical storage location. Not only RDBMS takes care of locating data it also determines an optimal access path to store or retrieve the data. Define SQL and state the differences between SQL and other conventional programming Languages SQL is a nonprocedural language that is designed specifically for data access operations on normalized relational database structures.
The primary difference between SQL and other conventional programming languages is that SQL statements specify what data operations should be performed rather than how to perform them. Name the three major set of files on disk that compose a database in Oracle There are three major sets of files on disk that compose a database.
All the files are binary. These are. The most important of these are the database files where the actual data resides. The control files and the redo logs support the functioning of the architecture itself. All three sets of files must be present, open, and available to Oracle for any data on the database to be useable. Without these files, you cannot access the database, and the database administrator might have to recover some or all of the database using a backup, if there is one.
What is an Oracle Instance? The Oracle system processes, also known as Oracle background processes, provide functions for the user processes—functions that would otherwise be done by the user processes themselves Oracle database-wide system memory is known as the SGA, the system global area or shared global area.
The data and control structures in the SGA are shareable, and all the Oracle background processes and user processes can use them. What are database files, control files and log files. How many of these files should a database have at least? Database Files The database files hold the actual data and are typically the largest in size.
You must have at least one database file but usually, more than one files are used. In terms of accessing and using the data in the tables and other objects, the number or location of the files is immaterial. The database files are fixed in size and never grow bigger than the size at which they were created Control Files The control files and redo logs support the rest of the architecture.
Any database must have at least one control file, although you typically have more than one to guard against loss. The control file records the name of the database, the date and time it was created, the location of the database and redo logs, and the synchronization information to ensure that all three sets of files are always in step.
Architecture is not only taking care of the structural and behavioral aspect of a software system but also taking into account the software usage, functionality, performance, reuse, economic and technology constraints. SDLC is a system including processes that are. What is the Life Cycle divided into? This Life cycle is divided into phases. Each Phase is a time span between two milestones. The milestones are. What are the Process Workflows that evolve through these phases?
The Process Workflows that evolve through these phases are. Dependencies are relationships between two entities. A change in specification of one thing may affect another thing. Most commonly it is used to show that one class uses another class as an argument in the signature of the operation. Generalization is relationships specified in the class subclass scenario, it is shown when one entity inherits from other.
Associations are structural relationships that are: a room has walls, Person works for a company. Aggregation is a type of association where there is a has a relationship. As in the following examples: A room has walls, or if there are two classes room and walls then the relation ship is called a association and further defined as an aggregation.
How are the diagrams divided? The nine diagrams are divided into static diagrams and dynamic diagrams. What are Messages?
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