Write any one similarity and one difference between primary key and unique Constraint -Technology

1 Answer

Answer :

Similarity: Column with both the constraints will only take unique values.Difference: Column with Primary key constraints will not be able to hold NULL values while Column with Unique constraints will be able to hold NULL values.

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Description : Write any one similarity and one difference between primary key and unique Constraint. -Technology

Last Answer : Similarity: Column with both the constraints will only take unique values.Difference: Column with Primary key constraints will not be able to hold NULL values while Column with Unique constraints will be able to hold NULL values.

Description : What is difference between UNIQUE constraint and PRIMARY KEY constraint ?

Last Answer : A column defined as UNIQUE can contain Nulls while a column defined as PRIMARY KEY can't contain Nulls.

Description : What is difference between UNIQUE constraint and PRIMARY KEY constraint?

Last Answer : A column defined as UNIQUE can contain Nulls while a column defined as PRIMARY KEY can’t contain Nulls. 47.What is Index Cluster? – A Cluster with an index on the Cluster Key 48.When does a Transaction end? – When it is committed or Rollbacked.

Description : If an unique key constraint on DATE column is created, will it validate the rows that are inserted with SYSDATE ?

Last Answer : It won't, Because SYSDATE format contains time attached with it.

Description : Drop Table cannot be used to drop a table referenced by a …………… constraint. A) Local Key B) Primary Key C) Composite Key D) Foreign Key

Last Answer : D) Foreign Key

Description : Drop Table cannot be used to drop a Table referenced by .................. constraint. (a) Primary key (b) Sub key (c) Super key (d) Foreign key (A) (a) (B) (a), (b) and (c) (C) (d) (D) (a) and (d)

Last Answer : (C) (d)

Description : Key field is a unique identifier for each record. It is defined in the form of (a) rows (b) columns -Technology

Last Answer : (b) Key is a data item that allows you to uniquely identify individual occurrences which is defined as the column or set of columns.

Description : What is the utility of primary key in database? Write distinct features of primary keys. -Technology

Last Answer : The primary key is used to uniquely identify the record in a database. It can be a column or a set of columns in the table.Main features of the primary key are as follows:1. It must contain a unique value for each record of the table.2. It does not contain null values.

Description : What is the difference between candidate key, unique key and primary key

Last Answer : Candidate keys are the columns in the table that could be the primary keys and the primary key is the key that has been selected to identify the rows. Unique key is also useful for identifying the distinct rows in the table.)

Description : What is difference between UNIQUE and PRIMARY KEY constraints?

Last Answer : A table can have only one PRIMARY KEY whereas there can be any number of UNIQUE keys. The columns that compose PK are automatically define NOT NULL, whereas a column that compose a UNIQUE is not automatically defined to be mandatory must also specify the column is NOT NULL.

Description : What is the difference between unique key and primary key ?

Last Answer : Unique key can be null; Primary key cannot be null.

Description : What is a primary key? -Technology

Last Answer : A field which uniquely identifies each record in a table is known as the primary key. e.g. emp id is the primary key of the Employee table.

Description : Define primary key with an example. -Technology

Last Answer : A field which uniquely identifies each record in a table is known as the primary key. e.g. emp id is the primary key of the Employee table.

Description : What is primary key? Give an example. -Technology

Last Answer : A field which uniquely identifies each record in a table is known as the primary key. e.g. emp id is the primary key of the Employee table.

Description : What is a primary key in database? Give an example. -Technology

Last Answer : A field which uniquely identifies each record in a table is known as the primary key. e.g. emp id is the primary key of the Employee table.

Description : Give one advantage of using primary key. -Technology

Last Answer : A primary key uniquely identifies the record in the table.

Description : What is the significance of a primary key? -Technology

Last Answer : A primary key cannot allow null values and must have a unique index.

Description : Which of the following fields will not make a suitable primary key? (a) A customer’s account number -Technology

Last Answer : (b) From the given options, the data field can not be set as a primary key because it can’t be fixed for an object.

Description : Primary key is used to …………….. identify the record. -Technology

Last Answer : Primary key is used to uniquelyidentify the record.

Description : The candidate key, which is not used as primary key is called ………….. key. -Technology

Last Answer : The candidate key, which is not used as primary key is calledalternate key.

Description : Primary key field gives us permission to record duplicate entry. -Technology

Last Answer : False A primary key is a key which identifies records uniquely in a table so it does not give us permission to record duplicate entry.

Description : A primary key field does not allow numbers. -Technology

Last Answer : False Primary key has to identify a unique value which can be present in a table, in a number form also. It means primary key field allow number too.

Description : A primary key value can be NULL. -Technology

Last Answer : False The primary key of table is used to uniquely identify each and every row in the table. So, its all keys and columns must be defined as NOT NULL.

Description : A foreign key is a primary key in another table. -Technology

Last Answer : True When a table’s primary key field is added to a related table in order to create the common field which relates two tables, it is called a foreign key in the related table.

Description : What is a primary key? How do we set a primary key? -Technology

Last Answer : Primary key is the key which is used to uniquely identify the records into the table. To set the primary key you have to follow the steps given below:Step 1 Select the field that you want ... 2 Click Primary Key button from the Design tab.orRight click on the selected field and select Primary Key.

Description : Define primary key. How do you set it in MS_Access? -Technology

Last Answer : Primary key is the key which is used to uniquely identify the records into the table. To set the primary key you have to follow the steps given below:Step 1 Select the field that you want ... 2 Click Primary Key button from the Design tab.orRight click on the selected field and select Primary Key.

Description : …………. is a field which is used as a primary key and numbers each record sequentially. -Technology

Last Answer : AutoNumberis a field which is used as a primary key and numbers each record sequentially.

Description : What is a primary key in a table? -Technology

Last Answer : A primary key is a special relational database table column (or combination of columns) designated to uniquely identify each & every table record. It does not contain NULL & duplicate values

Description : Identify the primary key column of Train and Reservation. -Technology

Last Answer : (i) Train-TrainIdReservation-RefNo(ii) (d) By default, the UNION operator selects all the values.

Description : Consider the following database table : Create table test( one integer, two integer, primary key(one), unique(two), check(one≥1 and ≤10), check(two≥1 and ≤5) ); How many data records/tuples atmost can this table contain ?  (A) 5 (B) 10 (C) 15 (D) 50

Last Answer : (A) 5 

Description : Describe the use of primary key and unique key constraints with example?

Last Answer : There are two Entity constraints: 1.Primary Key constraint 2. Unique Constraint 1. Primary Key constraint: It is use to avoid redundant/duplicate value entry within the row of specified column in ... TABLE PERSONS (P_ID NUM CONSTRAINT P_UK UNIQUE , FIRSTNAME VARCHAR(20), CITY VARCHAR(20) );

Description : What are the Referential actions supported by FOREIGN KEY integrity constraint ?

Last Answer : UPDATE and DELETE Restrict - A referential integrity rule that disallows the update or deletion of referenced data. DELETE Cascade - When a referenced row is deleted all associated dependent rows are deleted.

Description : What are the key components in the "Triple constraint Triangle"?  A. Scope, Schedule, Cost, Project Manager B. Scope, Time, Cost, Project (Ans.) C. Time, Money, Scope, Project D. Project Manager, Time, Scope, Money

Last Answer : B. Scope, Time, Cost, Project (Ans.)

Description : What are the Referential actions supported by FOREIGN KEY integrity constraint?

Last Answer : UPDATE and DELETE Restrict – A referential integrity rule that disallows the update or deletion of referenced data. DELETE Cascade – When a referenced row is deleted all associated dependent rows are deleted.

Description : In RDBMS, the constraint that no key attribute (column) may be NULL is referred to as: (A) Referential integrity (B) Multi-valued dependency (C) Entity Integrity (D) Functional dependency

Last Answer : (C) Entity Integrity

Description : Is the key similarity between the smartphone and the personal computer?

Last Answer : Need answer

Description : Write the significance of a foreign key. -Technology

Last Answer : A foreign key is used to Establish the relationship between any two tables of RDBMS.

Description : IP address is given to every computer for its unique identification. -Technology

Last Answer : True An IP address serves two principal functions:1. Host or network interface identification2. Location addressing

Description : A digital code attached to an electronic message to provide it unique identity is called ………… -Technology

Last Answer : A digital code attached to an electronic message to provide it unique identity is calleddigital signature.

Description : FTTC stands for: a. Fiber Transmission Timing Constraint b. Fiber Transmission Technology Committee c. Fiber Telephone Transmission Cable d. Fiber To The Curb

Last Answer : d. Fiber To The Curb

Description : The difference between the time avail-to do a job and the time required to do the job, is known as (A) Event (B) Float (C) Duration (D) Constraint

Last Answer : (B) Float

Description : Write two points of similarity between sherardizing and galvanising process.

Last Answer : 1) Sherardizing and galvanizing are the processes of avoiding corrosion of metal. 2) Zinc is used as coating metal on iron base metal.

Description : A foreign key is a reference of the ………….. key in another table. -Technology

Last Answer : A foreign key is a reference of the primary keyin another table.

Description : Which shortcut key is used to make the selected text italic? (a) Ctrl +I (b) Shift +I (c) F1 + I (d) None of these -Technology

Last Answer : (a) Ctrl+I is the shortcut key to make the selected text italic.

Description : What is the use of Enter and Esc key in a Slide Show? -Technology

Last Answer : Press Enter to move to the next slide and Esc to close the Slide Show.

Description : Set new timing, while rehearsing ……………… key is press. (a) Ctrl+T (b) T (c) M (d) O -Technology

Last Answer : (b) T key is used to set new timing while rehearsing.

Description : What is the shortcut key to display the Microsoft PowerPoint shortcut menu? -Technology

Last Answer : (c) Shift + F10 is the shortcut key to display the PowerPoint shortcut menu

Description : F4 key is used to start a Slide Show. -Technology

Last Answer : FalseF5 key is used to start a Slide Show.

Description : The contents of a cell can be changed by pressing F2 key on keyboard. -Technology

Last Answer : True F2 is a shortcut for making the cell editable.

Description : What’s the .NET collection class that allows an element to be accessed using a unique key? 

Last Answer : HashTable.