Interview Questions.

Question 1. What Is Rdbms?

Answer :

Relational Data Base Management Systems (RDBMS) are database control structures that maintain information facts and indices in tables. Relationships can be created and maintained across and among the records and tables. In a relational database, relationships among records gadgets are expressed through tables. Interdependencies amongst those tables are expressed by way of statistics values in preference to by means of suggestions. This lets in a excessive degree of facts independence. An RDBMS has the functionality to recombine the statistics items from unique files, presenting powerful equipment for records utilization.

Question 2. What Is Normalization?

Answer :

Database normalization is a records design and business enterprise procedure implemented to data structures based on rules that help build relational databases. In relational database layout, the manner of organizing information to decrease redundancy. Normalization commonly entails dividing a database into two or greater tables and defining relationships between the tables. The objective is to isolate records so that additions, deletions, and modifications of a field may be made in just one desk and then propagated thru the rest of the database via the defined relationships.

ETL Testing Interview Questions
Question three. What Are Different Normalization Forms?

Answer :

1NF: Eliminate Repeating Groups Make a separate desk for each set of related attributes, and supply each desk a number one key. Each area incorporates at most one value from its characteristic domain.

2NF: Eliminate Redundant Data If an characteristic depends on best a part of a multi-valued key, dispose of it to a separate desk.

3NF: Eliminate Columns Not Dependent On Key If attributes do no longer contribute to an outline of the key, get rid of them to a separate desk. All attributes ought to be at once depending on the number one key.

BCNF: Boyce-Codd Normal Form If there are non-trivial dependencies between candidate key attributes, separate them out into distinct tables.

4NF: Isolate Independent Multiple Relationships No desk may additionally include  or more 1:n or n:m relationships that aren't at once related.

5NF: Isolate Semantically Related Multiple Relationships There can be sensible constrains on statistics that justify setting apart logically related many-to-many relationships.

ONF: Optimal Normal Form A version restricted to simplest simple (elemental) information, as expressed in Object Role Model notation.

DKNF: Domain-Key Normal Form A version unfastened from all amendment anomalies. Remember, those normalization pointers are cumulative. For a database to be in 3NF, it ought to first fulfill all the criteria of a 2NF and 1NF database.

Question four. What Is Stored Procedure?

Answer :

A saved manner is a named institution of SQL statements which have been previously created and saved inside the server database. Stored processes receive input parameters so that a unmarried process may be used over the network via several customers using exclusive input information. And when the system is changed, all clients mechanically get the new version. Stored tactics lessen network site visitors and improve performance. Stored strategies can be used to help ensure the integrity of the database.
E.G. Sp_helpdb, sp_renamedb, sp_depends etc.

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Question five. What Is Trigger?

Answer :

A cause is a SQL manner that initiates an action whilst an occasion (INSERT, DELETE or UPDATE) occurs. Triggers are saved in and controlled with the aid of the DBMS. Triggers are used to maintain the referential integrity of data by using converting the records in a scientific style. A cause cannot be called or carried out; the DBMS automatically fires the trigger due to a data amendment to the associated desk. Triggers can be viewed as much like saved approaches in that both consist of procedural common sense that is saved on the database stage. Stored techniques, but, aren't occasion-force and aren't attached to a particular desk as triggers are. Stored methods are explicitly finished by means of invoking a CALL to the system at the same time as triggers are implicitly performed. In addition, triggers can also execute stored methods.

SQL Server 2008 Interview Questions
Question 6. What Is View?

Answer :

A simple view can be concept of as a subset of a desk. It can be used for retrieving information, as well as updating or deleting rows. Rows updated or deleted in the view are up to date or deleted inside the desk the view turned into created with. It need to additionally be stated that as records in the original desk modifications, so does statistics in the view, as views are the manner to have a look at part of the original desk. The results of using a view are not completely saved inside the database. The data accessed thru a view is virtually constructed the use of general T-SQL pick command and may come from one to many different base tables or even different perspectives.

Question 7. What Is Index?

Answer :

An index is a physical shape containing recommendations to the statistics. Indices are created in an present desk to find rows more fast and efficaciously. It is possible to create an index on one or more columns of a table, and every index is given a call. The customers can't see the indexes, they're just used to speed up queries. Effective indexes are one of the satisfactory ways to enhance performance in a database application. A table test takes place while there is no index to be had to help a query. In a desk test SQL Server examines each row inside the table to fulfill the question consequences. Table scans are sometimes unavoidable, but on huge tables, scans have a remarkable impact on performance. Clustered indexes define the bodily sorting of a database table’s rows inside the garage media. For this reason, every database table can also have only one clustered index. Non-clustered indexes are created outdoor of the database desk and include a taken care of listing of references to the table itself.

SQL Server 2008 Tutorial SQL Database Interview Questions
Question 8. What Is Database?

Answer :

A database is a logically coherent collection of records with a few inherent which means, representing some factor of real world and which is designed, built and populated with records for a specific purpose.

Question 9. What Is Dbms?

Answer :

It is a set of applications that enables person to create and preserve a database. In other words it is standard-motive software program that offers the customers with the approaches of defining, constructing and manipulating the database for diverse programs.

Oracle 11g Interview Questions
Question 10. What Is A Database System?

Answer :

The database and DBMS software together is referred to as as Database machine.

SQL Database Tutorial
Question 11. Advantages Of Dbms?

Answer :

 Redundancy is managed.
 Unauthorised get entry to is limited.
 Providing more than one consumer interfaces.
 Enforcing integrity constraints.
 Providing backup and healing.
PostgreSQL Interview Questions
Question 12. Disadvantage In File Processing System?

Answer :

 Data redundancy & inconsistency.
 Difficult in having access to records.
 Data isolation.
 Data integrity.
 Concurrent get admission to is not viable.
 Security Problems.
ETL Testing Interview Questions
Question thirteen. Describe The Three Levels Of Data Abstraction?

Answer :

There are three levels of abstraction:

 Physical stage: The lowest stage of abstraction describes how information are saved.
 Logical stage: The subsequent better degree of abstraction, describes what statistics are saved in database and what dating among those records.
 View degree: The maximum stage of abstraction describes simplest a part of entire database.
Oracle 11g Tutorial
Question 14. Define The "integrity Rules"?

Answer :

There are two Integrity policies.

 Entity Integrity: States that “Primary key can't have NULL price”.
 Referential Integrity: States that “Foreign Key may be both a NULL price or need to be Primary Key fee of different relation.
Question 15. What Is Extension And Intension?

Answer :

Extension : It is the number of tuples present in a desk at any example. This is time structured.

Intension : It is a steady cost that offers the call, structure of desk and the limitations laid on it.

SQL DBA Interview Questions
Question sixteen. What Is System R? What Are Its Two Major Subsystems?

Answer :

System R turned into designed and developed over a length of 1974-seventy nine at IBM San Jose Research Center. It is a prototype and its reason become to illustrate that it is possible to construct a Relational System that can be utilized in a real lifestyles environment to resolve actual life issues, with overall performance at least comparable to that of present device.
Its two subsystems are

 Research Storage
 System Relational Data System.
Apache Cassandra Tutorial
Question 17. How Is The Data Structure Of System R Different From The Relational Structure?

Answer :

Unlike Relational structures in System R

 Domains aren't supported
 Enforcement of candidate key uniqueness is elective
 Enforcement of entity integrity is elective
 Referential integrity is not enforced
SSRS(SQL Server Reporting Services) Interview Questions
Question 18. What Is Data Independence?

Answer :

Data independence method that “the software is independent of the storage shape and get admission to approach of statistics”. In other words, The potential to adjust the schema definition in one degree need to now not affect the schema definition inside the subsequent higher degree.
Two types of Data Independence:

 Physical Data Independence: Modification in bodily stage ought to now not affect the logical level.
 Logical Data Independence: Modification in logical level must affect the view degree.
SQL Server 2008 Interview Questions
Question 19. What Is A View? How It Is Related To Data Independence?

Answer :

A view may be notion of as a virtual table, that is, a table that doesn't truely exist in its very own right but is as a substitute derived from one or more underlying base desk. In other words, there is no saved record that direct represents the view rather a definition of view is stored in data dictionary. Growth and restructuring of base tables is not contemplated in views. Thus the view can insulate customers from the effects of restructuring and boom within the database. Hence money owed for logical information independence.

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Question 20. What Is Data Model?

Answer :

A collection of conceptual gear for describing information, data relationships information semantics and constraints.

MYSQL DBA Interview Questions
Question 21. What Is E-r Model?

Answer :

This statistics version is based on real global that includes basic items referred to as entities and of relationship amongst those objects. Entities are described in a database with the aid of a set of attributes.

Question 22. What Is Object Oriented Model?

Answer :

This model is based on series of objects. An object includes values saved in instance variables with in the object. An item also contains bodies of code that function at the object. These our bodies of code are called methods. Objects that include same varieties of values and the equal techniques are grouped together into training.

Question 23. What Is An Entity?

Answer :

It is a 'thing' in the actual international with an unbiased existence.

IBM Websphere Application Server Interview Questions
Question 24. What Is An Entity Type?

Answer :

It is a group (set) of entities which have identical attributes.

SQL Database Interview Questions
Question 25. What Is An Entity Set?

Answer :

It is a group of all entities of specific entity kind within the database.

Question 26. What Is An Extension Of Entity Type?

Answer :

The collections of entities of a selected entity type are grouped collectively into an entity set.

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Question 27. What Is Weak Entity Set?

Answer :

An entity set won't have sufficient attributes to shape a primary key, and its number one key compromises of its partial key and primary key of its figure entity, then it is said to be Weak Entity set.

Oracle 11g Interview Questions
Question 28. What Is An Attribute?

Answer :

It is a particular property, which describes the entity.

Question 29. What Is A Relation Schema And A Relation?

Answer :

A relation Schema denoted by using R(A1, A2, …, An) is made from the relation name R and the list of attributes Ai that it includes.

A relation is defined as a set of tuples. Let r be the relation which incorporates set tuples (t1, t2, t3, ..., tn). Each tuple is an ordered listing of n-values t=(v1,v2, ..., vn).

MongoDB Interview Questions
Question 30. What Is Degree Of A Relation?

Answer :

It is the number of characteristic of its relation schema.

Question 31. What Is Relationship?

Answer :

It is an association among  or more entities.

Question 32. What Is Relationship Set?

Answer :

The series (or set) of comparable relationships.

Sql Loader Interview Questions
Question 33. What Is Relationship Type?

Answer :

Relationship kind defines a set of institutions or a dating set among a given set of entity kinds.

PostgreSQL Interview Questions
Question 34. What Is Degree Of Relationship Type?

Answer :

It is the range of entity type taking part.

Question 35. What Is Ddl (records Definition Language)?

Answer :

A information base schema is specifies by means of a hard and fast of definitions expressed with the aid of a special language known as DDL.

Question 36. What Is Vdl (view Definition Language)?

Answer :

It specifies consumer perspectives and their mappings to the conceptual schema.

SQL DBA Interview Questions
Question 37. What Is Sdl (garage Definition Language)?

Answer :

This language is to specify the inner schema. This language may additionally specify the mapping among two schemas.

Question 38. What Is Data Storage - Definition Language?

Answer :

The storage structures and access techniques utilized by database system are certain with the aid of a fixed of definition in a special kind of DDL known as facts storage-definition language.

Question 39. What Is Dml (information Manipulation Language)?

Answer :

This language that permit user to get entry to or manage statistics as organized by suitable statistics model.

 Procedural DML or Low degree: DML requires a user to specify what statistics are needed and how to get the ones records.
 Non-Procedural DML or High level: DML requires a consumer to specify what information are needed with out specifying the way to get the ones facts.
Question 40. What Is Dml Compiler?

Answer :

It translates DML statements in a query language into low-stage guidance that the question assessment engine can apprehend.

SSRS(SQL Server Reporting Services) Interview Questions
Question 41. What Is Query Evaluation Engine?

Answer :

It executes low-level guidance generated by way of compiler.

Question 42. What Is Ddl Interpreter?

Answer :

It interprets DDL statements and file them in tables containing metadata.

MYSQL DBA Interview Questions
Question forty three. What Is Record-at-a-time?

Answer :

The Low stage or Procedural DML can specify and retrieve every file from a hard and fast of facts. This retrieve of a report is stated to be Record-at-a-time.

Question 44. What Is Set-at-a-time Or Set-orientated?

Answer :

The High degree or Non-procedural DML can specify and retrieve many information in a single DML declaration. This retrieve of a file is said to be Set-at-a-time or Set-orientated.

Question forty five. What Is Relational Algebra?

Answer :

It is procedural question language. It consists of a set of operations that take one or two members of the family as input and convey a brand new relation.

Question 46. What Is Relational Calculus?

Answer :

It is an carried out predicate calculus specifically tailored for relational databases proposed by means of E.F. Codd.
E.G. Of languages primarily based on it are DSL ALPHA, QUEL.

Question forty seven. How Does Tuple-orientated Relational Calculus Differ From Domain-orientated Relational Calculus?

Answer :

The tuple-oriented calculus uses a tuple variables i.E., variable whose handiest accepted values are tuples of that relation. E.G. QUEL
The area-oriented calculus has area variables i.E., variables that variety over the underlying domain names in place of over relation. E.G. ILL, DEDUCE.

Question 48. What Is Functional Dependency?

Answer :

A Functional dependency is denoted by way of X Y among two units of attributes X and Y which can be subsets of R specifies a constraint at the feasible tuple that can form a relation nation r of R. The constraint is for any  tuples t1 and t2 in r if t1[X] = t2[X] then they've t1[Y] = t2[Y]. This means the price of X element of a tuple uniquely determines the fee of element Y.

Question forty nine. When Is A Functional Dependency F Said To Be Minimal?

Answer :

 Every dependency in F has a single attribute for its proper hand aspect.
 We can not update any dependency X A in F with a dependency Y A in which Y is a proper subset of X and also have a set of dependency this is equivalent to F.
 We cannot take away any dependency from F and now have set of dependency that is equal to F.
Question 50. What Is Multivalued Dependency?

Answer :

Multivalued dependency denoted through X Y certain on relation schema R, where X and Y are both subsets of R, specifies the following constraint on any relation r of R: if two tuples t1 and t2 exist in r such that t1[X] = t2[X] then t3 and t4 should additionally exist in r with the following properties

 t3[x] = t4[X] = t1[X] = t2[X]
 t3[Y] = t1[Y] and t4[Y] = t2[Y]
 t3[Z] = t2[Z] and t4[Z] = t1[Z]
wherein [Z = (R-(X U Y)) ]

Question 51. What Is Lossless Join Property?

Answer :

It ensures that the spurious tuple era does now not occur with respect to relation schemas after decomposition.

Question fifty two. What Is 1 Nf (regular Form)?

Answer :

The area of attribute should encompass handiest atomic (easy, indivisible) values.

Question 53. What Is Fully Functional Dependency?

Answer :

It is based on idea of full useful dependency. A practical dependency X Y is full practical dependency if removal of any characteristic A from X way that the dependency does not keep any extra.

Question fifty four. What Is 2nf?

Answer :

A relation schema R is in 2NF if it's far in 1NF and every non-prime characteristic A in R is completely functionally depending on primary key.

Question fifty five. What Is 3nf?

Answer :

A relation schema R is in 3NF if it's miles in 2NF and for every FD X A either of the subsequent is real

 X is a Super-key of R.
 A is a prime characteristic of R.
In other phrases, if every non prime characteristic is non-transitively depending on primary key.

Question fifty six. What Is Bcnf (boyce-codd Normal Form)?

Answer :

A relation schema R is in BCNF if it's far in 3NF and satisfies a further constraint that for each FD X A, X ought to be a candidate key.

Question fifty seven. What Is 4nf?

Answer :

A relation schema R is stated to be in 4NF if for every Multivalued dependency X Y that holds over R, one in every of following is real

 X is subset or same to (or) XY = R.
 X is a brilliant key.
Question fifty eight. What Is 5nf?

Answer :

A Relation schema R is said to be 5NF if for every be part of dependency R1, R2, ..., Rn that holds R, one the subsequent is authentic

 Ri = R for a few i.
 The be part of dependency is implied with the aid of the set of FD, over R wherein the left side is prime of R.
Question 59. What Is Domain-key Normal Form?

Answer :

A relation is said to be in DKNF if all constraints and dependencies that ought to maintain at the constraint may be enforced through definitely enforcing the area constraint and key constraint on the relation.

Question 60. What Are Partial, Alternate, Artificial, Compound And Natural Key?

Answer :

Partial Key:
It is a set of attributes which can uniquely pick out vulnerable entities and which are associated with same proprietor entity. It is someday called as Discriminator.

Alternate Key:
All Candidate Keys excluding the Primary Key are known as Alternate Keys.

Artificial Key:
If no obvious key, both stand on my own or compound is available, then the final resort is to in reality create a key, by way of assigning a unique wide variety to every record or prevalence. Then that is known as growing an artificial key.

Compound Key:
If no unmarried facts element uniquely identifies occurrences inside a construct, then combining more than one elements to create a unique identifier for the construct is known as creating a compound key.

Natural Key:
When one of the data elements stored within a construct is utilized as the number one key, then it is called the herbal key.

Question sixty one. What Is Indexing And What Are The Different Kinds Of Indexing?

Answer :

Indexing is a technique for determining how quickly unique records can be found.
Types:

 Binary search fashion indexing
 B-Tree indexing
 Inverted listing indexing
 Memory resident table
 Table indexing
Question 62. What Is System Catalog Or Catalog Relation? How Is Better Known As?

Answer :

A RDBMS continues a description of all the statistics that it contains, information about each relation and index that it incorporates. This records is saved in a group of family members maintained via the gadget called metadata. It is also called records dictionary.

Question 63. What Is Meant By Query Optimization?

Answer :

The section that identifies an efficient execution plan for comparing a question that has the least expected fee is known as question optimization.

Question 64. What Is Join Dependency And Inclusion Dependency?

Answer :

Join Dependency:

A Join dependency is generalization of Multivalued dependency.A JD R1, R2, ..., Rn is said to hold over a relation R if R1, R2, R3, ..., Rn is a lossless-join decomposition of R . There is not any set of sound and complete inference rules for JD.

Inclusion Dependency:

An Inclusion Dependency is a assertion of the form that a few columns of a relation are contained in other columns. A overseas key constraint is an instance of inclusion dependency.

Question sixty five. What Is Durability In Dbms?

Answer :

Once the DBMS informs the person that a transaction has efficaciously completed, its outcomes have to persist although the device crashes before all its adjustments are contemplated on disk. This belongings is referred to as durability.

Question sixty six. What Do You Mean By Atomicity And Aggregation?

Answer :

Atomicity:
Either all moves are completed or none are. Users have to no longer have to fear about the effect of incomplete transactions. DBMS ensures this via undoing the actions of incomplete transactions.
Aggregation:
A idea that is used to model a relationship among a set of entities and relationships. It is used when we need to express a dating amongst relationships.

Question sixty seven. What Is A Phantom Deadlock?

Answer :

In disbursed impasse detection, the put off in propagating local statistics may purpose the impasse detection algorithms to perceive deadlocks that do not in reality exist. Such conditions are referred to as phantom deadlocks and that they result in unnecessary aborts.

Question sixty eight. What Is A Checkpoint And When Does It Occur?

Answer :

A Checkpoint is like a image of the DBMS state. By taking checkpoints, the DBMS can lessen the amount of work to be performed throughout restart inside the occasion of subsequent crashes.

Question sixty nine. What Are The Different Phases Of Transaction?

Answer :

Different phases are

 Analysis phase
 Redo Phase
 Undo phase
Question 70. What Do You Mean By Flat File Database?

Answer :

It is a database in which there are no programs or person get entry to languages. It has no pass-report abilties however is person-friendly and presents person-interface management.

Question 71. What Is "transparent Dbms"?

Answer :

It is one, which maintains its Physical Structure hidden from person.

Question seventy two. Brief Theory Of Network, Hierarchical Schemas And Their Properties?

Answer :

Network schema uses a graph statistics shape to arrange statistics example for the sort of database control system is CTCG whilst a hierarchical schema makes use of a tree records structure instance for this kind of machine is IMS.

Question 73. What Is A Query?

Answer :

A query with respect to DBMS pertains to user instructions which might be used to engage with a records base. The query language can be labeled into facts definition language and facts manipulation language.

Question seventy four. What Do You Mean By Correlated Subquery?

Answer :

Subqueries, or nested queries, are used to deliver returned a set of rows to be used by the parent question. Depending on how the subquery is written, it is able to be accomplished once for the parent question or it can be completed once for each row again through the discern query. If the subquery is achieved for each row of the parent, this is called a correlated subquery.
A correlated subquery can be without problems identified if it incorporates any references to the parent subquery columns in its WHERE clause. Columns from the subquery cannot be referenced anywhere else inside the determine query. The following instance demonstrates a non-correlated subquery.
E.G. Select * From CUST Where '10/03/1990' IN (Select ODATE From ORDER Where CUST.CNUM = ORDER.CNUM)

Question 75. What Are The Primitive Operations Common To All Record Management Systems?

Answer :

Addition, deletion and change.

Question seventy six. Name The Buffer In Which All The Commands That Are Typed In Are Stored?

Answer :

‘Edit’ Buffer.

Question 77. What Are The Unary Operations In Relational Algebra?

Answer :

PROJECTION and SELECTION.

Question 78. Are The Resulting Relations Of Product And Join Operation The Same?

Answer :

No.
PRODUCT: Concatenation of every row in a single relation with every row in some other.
JOIN: Concatenation of rows from one relation and related rows from some other.

Question 79. What Is Rdbms Kernel?

Answer :

Two vital pieces of RDBMS architecture are the kernel, that is the software, and the records dictionary, which includes the gadget-degree statistics structures utilized by the kernel to manage the database
You may think of an RDBMS as an running device (or set of subsystems), designed specifically for controlling data get right of entry to; its primary features are storing, retrieving, and securing facts. An RDBMS maintains its own list of legal customers and their related privileges; manages memory caches and paging; controls locking for concurrent useful resource utilization; dispatches and schedules user requests; and manages space usage within its desk-space structures.

Question eighty. Name The Sub-structures Of A Rdbms?

Answer :

I/O, Security, Language Processing, Process Control, Storage Management, Logging and Recovery, Distribution Control, Transaction Control, Memory Management, Lock Management.

Question 81. Which Part Of The Rdbms Takes Care Of The Data Dictionary? How

Answer :

Data dictionary is a set of tables and database items that is stored in a special vicinity of the database and maintained completely with the aid of the kernel.

Question eighty two. What Is The Job Of The Information Stored In Data-dictionary?

Answer :

The information inside the records dictionary validates the existence of the objects, presents get admission to to them, and maps the real physical garage area.

Question eighty three. Not Only Rdbms Takes Care Of Locating Data It Also?

Answer :

determines an most efficient get right of entry to route to shop or retrieve the statistics.

Question eighty four. How Do You Communicate With An Rdbms?

Answer :

You speak with an RDBMS the usage of Structured Query Language (SQL).

Question 85. Define Sql And State The Differences Between Sql And Other Conventional Programming Languages?

Answer :

SQL is a nonprocedural language this is designed especially for facts get right of entry to operations on normalized relational database structures. The primary distinction among SQL and different traditional programming languages is that SQL statements specify what records operations must be accomplished as opposed to a way to carry out them.

Question 86. Name The Three Major Set Of Files On Disk That Compose A Database In Oracle?

Answer :

There are 3 most important units of files on disk that compose a database. All the documents are binary. These are

 Database files
 Control documents
 Redo logs
The most crucial of these are the database files wherein the actual facts resides. The control files and the redo logs help the functioning of the architecture itself.
All 3 sets of documents need to be gift, open, and available to Oracle for any facts at the database to be useable. Without those documents, you cannot access the database, and the database administrator would possibly need to get better some or all of the database the use of a backup, if there is one.

Question 87. What Is An Oracle Instance?

Answer :

The Oracle device processes, also called Oracle historical past strategies, provide capabilities for the person techniques—features that might in any other case be completed by the consumer approaches themselves Oracle database-extensive system memory is known as the SGA, the gadget international region or shared worldwide vicinity. The data and manage structures in the SGA are shareable, and all of the Oracle historical past approaches and person tactics can use them.
The combination of the SGA and the Oracle historical past approaches is called an Oracle example.

Question 88. What Are The Four Oracle System Processes That Must Always Be Up And Running For The Database To Be Useable

Answer :

The 4 Oracle gadget processes that need to constantly be up and strolling for the database to be useable consist of DBWR (Database Writer), LGWR (Log Writer), SMON (System Monitor), and PMON (Process Monitor).

Question 89. What Is Rowid?

Answer :

The ROWID is a completely unique database-wide physical cope with for each row on every table. Once assigned (while the row is first inserted into the database), it in no way modifications till the row is deleted or the table is dropped.
The ROWID consists of the subsequent three additives, the mixture of which uniquely identifies the physical storage vicinity of the row.

 Oracle database report wide variety, which includes the block with the rows
 Oracle block deal with, which incorporates the row
 The row in the block (because every block can maintain many rows)
The ROWID is used internally in indexes as a brief method of retrieving rows with a selected key value. Application developers additionally use it in SQL statements as a brief manner to get entry to a row when they recognize the ROWID.

Question 90. What Is Oracle Block? Can Two Oracle Blocks Have The Same Address?

Answer :

Oracle "formats" the database files into a number of Oracle blocks whilst they're first created—making it less complicated for the RDBMS software program to control the files and simpler to study statistics into the reminiscence regions.
The block length have to be a more than one of the working system block length. Regardless of the block length, the whole block isn't to be had for containing data; Oracle takes up some area to manage the contents of the block. This block header has a minimal length, however it can develop.
These Oracle blocks are the smallest unit of storage. Increasing the Oracle block size can improve performance, however it must be finished handiest when the database is first created.
Each Oracle block is numbered sequentially for every database record beginning at 1. Two blocks may have the identical block address if they're in different database files.

Question 91. What Is Database Trigger?

Answer :

A database cause is a PL/SQL block which can defined to robotically execute for insert, update, and delete statements in opposition to a desk. The cause can be described to execute once for the entire assertion or once for every row that is inserted, up to date, or deleted. For any person desk, there are twelve events for which you may define database triggers. A database cause can name database methods that are additionally written in PL/SQL.

Question 92. Name Two Utilities That Oracle Provides, Which Are Use For Backup And Recovery.

Answer :

Along with the RDBMS software program, Oracle offers  utilities that you can use to again up and repair the database. These utilities are Export and Import.
The Export software dumps the definitions and statistics for the specified part of the database to an working device binary document. The Import utility reads the file produced with the aid of an export, recreates the definitions of gadgets, and inserts the facts.
If Export and Import are used as a method of backing up and recuperating the database, all the changes made to the database cannot be recovered because the export turned into finished. The pleasant you could do is recover the database to the time whilst the export become last accomplished.

Question 93. What Are Stored-tactics? And What Are The Advantages Of Using Them.

Answer :

Stored tactics are database gadgets that perform a person defined operation. A stored system can have a fixed of compound SQL statements. A stored procedure executes the SQL commands and returns the result to the consumer. Stored techniques are used to reduce community visitors.

Question ninety four. Does Pl/square Support "overloading"? Explain

Answer :

The idea of overloading in PL/SQL relates to the idea that you may outline processes and functions with the same name. PL/SQL does now not appearance simplest at the referenced name, however, to solve a method or feature call. The count and facts styles of formal parameters are also taken into consideration.
PL/SQL also attempts to clear up any technique or feature calls in locally defined programs earlier than searching at globally defined applications or inner functions. To similarly ensure calling the proper method, you could use the dot notation. Prefacing a manner or function name with the package call fully qualifies any system or function reference.

Question ninety five. What Is Storage Manager?

Answer :

It is a software module that offers the interface among the low-stage statistics stored in database, application packages and queries submitted to the device.

Question 96. What Is Buffer Manager?

Answer :

It is a application module, which is answerable for fetching information from disk storage into principal reminiscence and finding out what data to be cache in reminiscence.

Question ninety seven. What Is Transaction Manager?

Answer :

It is a application module, which ensures that database, remains in a regular nation no matter system disasters and concurrent transaction execution proceeds with out conflicting.

Question 98. What Is File Manager?

Answer :

It is a software module, which manages the allocation of space on disk storage and data structure used to symbolize records saved on a disk.

Question 99. What Is Authorization And Integrity Manager?

Answer :

It is this system module, which exams for the delight of integrity constraint and assessments the authority of consumer to get admission to information.

Question 100. What Are Stand-by myself Procedures?

Answer :

Procedures that are not part of a package are known as stand-by myself because they independently defined. A accurate example of a stand-on my own method is one written in a SQL*Forms application. These types of tactics are not available for reference from other Oracle gear. Another challenge of stand-on my own procedures is that they are compiled at run time, which slows execution.

Question one hundred and one. What Are Cursors Give Different Types Of Cursors.

Answer :

PL/SQL uses cursors for all database information accesses statements. The language helps the use  sorts of cursors.

 Implicit
 Explicit
Question 102. What Is Meant By Proactive, Retroactive And Simultaneous Update?

Answer :

Proactive Update:
The updates which might be implemented to database before it becomes effective in real global .

Retroactive Update:
The updates which might be applied to database after it will become powerful in real international.

Simultaneous Update:
The updates which are applied to database at the same time when it will become effective in actual world .