Can a primary key contain more than one columns?

Can a primary key contain more than one columns?
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Yes
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Related questions

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

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.)

What is difference between UNIQUE and PRIMARY KEY constraints?

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.

What is difference between UNIQUE constraint and PRIMARY KEY constraint ?

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.

Can you disable and enable Primary key?

Description : Can you disable and enable Primary key?

Last Answer : You can use the ALTER TABLE statement to enable, disable, modify, or drop a constraint. When the database is using a UNIQUE or PRIMARY KEY index to enforce a constraint, and constraints associated ... and any FOREIGN KEY constraints that depend on it: ALTER TABLE dept DISABLE PRIMARY KEY CASCADE;

In a relational database model, NULL values can be used for all but which one of the following? (A) To allow duplicate tuples in the table by filling the primary key column(s) with NULL. (B) To avoid confusion with actual legitimate data values like 0 (zero) for integer columns and ‘’ (the empty string) for string columns. (C) To leave columns in a tuple marked as “unknown” when the actual value is unknown. (D) To fill a column in a tuple when that column does not really “exist” for that particular tuple.

Description : In a relational database model, NULL values can be used for all but which one of the following? (A) To allow duplicate tuples in the table by filling the primary key column(s) with NULL. (B) To ... D) To fill a column in a tuple when that column does not really exist for that particular tuple.

Last Answer : (A) To allow duplicate tuples in the table by filling the primary key column(s) with NULL.

How do you use the same lov for 2 columns

Description : How do you use the same lov for 2 columns

Last Answer : We can use the same lov for 2 columns by passing the return values in global values and using the global values in the code

How many number of columns a record group can have?

Description : How many number of columns a record group can have?

Last Answer : A record group can have an unlimited number of columns of type CHAR, LONG, NUMBER, or DATE provided that the total number of column does not exceed 64K.

Can a formula column referred to columns in higher group?

Description : Can a formula column referred to columns in higher group?

Last Answer : Yes

How many types of columns are there and what are they

Description : How many types of columns are there and what are they

Last Answer : Formula columns :: For doing mathematical calculations and returning one value Summary Columns :: For doing summary calculations such as summations etc. Place holder Columns :: These columns are useful for storing the value in a variable

How many columns can table have?

Description : How many columns can table have?

Last Answer : The number of columns in a table can range from 1 to 254.

What is pseudo columns ? Name them?

Description : What is pseudo columns ? Name them?

Last Answer : A pseudocolumn behaves like a table column, but is not actually stored in the table. You can select from pseudocolumns, but you cannot insert, update, or delete their values. This section describes these pseudocolumns: * CURRVAL * NEXTVAL * LEVEL * ROWID * ROWNUM

Suppose a customer table is having different columns like customer no, payments.What will be the query to select top three max payments?

Description : Suppose a customer table is having different columns like customer no, payments.What will be the query to select top three max payments?

Last Answer : SELECT customer_no, payments from customer C1 WHERE 3

How many LONG columns are allowed in a table ? Is it possible to use LONG columns in WHERE clause or ORDER BY ?

Description : How many LONG columns are allowed in a table ? Is it possible to use LONG columns in WHERE clause or ORDER BY ?

Last Answer : Only one LONG columns is allowed. It is not possible to use LONG column in WHERE or ORDER BY clause.

If a break order is set on a column would it affect columns which are under the column?

Description : If a break order is set on a column would it affect columns which are under the column?

Last Answer : No

What are the types of calculated columns available?

Description : What are the types of calculated columns available?

Last Answer : Summary, Formula, Placeholder column.

On which columns you should create Indexes?

Description : On which columns you should create Indexes?

Last Answer : In general, you should create an index on a column in any of the following situations: ▪ The column is queried frequently ▪ A referential integrity constraint exists on the column ▪ A UNIQUE key ... ORDER BY clauses ▪ On columns that have few of the same values or unique values in the table

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

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 

Do a view contain data?

Description : Do a view contain data?

Last Answer : Views do not contain or store data.

What does a Control file Contain ?

Description : What does a Control file Contain ?

Last Answer : A Control file records the physical structure of the database. It contains the following information. Database Name Names and locations of a database's files and redolog files. Time stamp of database creation.

Do View contain Data ?

Description : Do View contain Data ?

Last Answer : Views do not contain or store data.

what are key-mode and locking mode properties? level ?

Description : what are key-mode and locking mode properties? level ?

Last Answer : Key Mode : Specifies how oracle forms uniquely identifies rows in the database.This is property includes for application that will run against NON-ORACLE datasources . Key setting unique (default.) ... locks on rows that correspond to queried records in the form. a) immediate b) delayed

Key Words Used in Oracle

Description : Key Words Used in Oracle

Last Answer : The Key words that are used in Oracle are :: a) Commiting :: A transaction is said to be commited when the transaction makes permanent changes resulting from the SQL statements. b) Rollback :: ... A Process is a 'thread of control' or mechansim in Operating System that executes series of steps.

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

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.

What is the difference between a Function Key Trigger and Key Function Trigger ?

Description : What is the difference between a Function Key Trigger and Key Function Trigger ?

Last Answer : Function key triggers are associated with individual SQL*FORMS function keys You can attach Key function triggers to 10 keys or key sequences that normally do not perform any SQL * FORMS operations. These keys referred as key F0 through key F9.

What are the different types of key triggers ?

Description : What are the different types of key triggers ?

Last Answer : Function Key Key-function Key-others Key-startup

Is a Key startup trigger fires as result of a operator pressing a key explicitly ?

Description : Is a Key startup trigger fires as result of a operator pressing a key explicitly ?

Last Answer : No

What is cluster key?

Description : What is cluster key?

Last Answer : The related columns of the tables in a cluster are called the cluster key.

What is a cluster Key ?

Description : What is a cluster Key ?

Last Answer : The related columns of the tables are called the cluster key. The cluster key is indexed using a cluster index and its value is stored only once for multiple tables in the cluster.

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

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

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HOW MANY SEGMENTS ARE THERE IN THE KEY FLEXFIELD(S) IN ORACLE GENERAL LEDGER?

Description : HOW MANY SEGMENTS ARE THERE IN THE KEY FLEXFIELD(S) IN ORACLE GENERAL LEDGER?

Last Answer : - Oracle GL Key flexfield can have 15 columns each representing a segment. However, the segments type can be:  Cost Center segment  Balancing segment  Account segment  Intercompany segment

WHAT IS A KEY FLEXFIELD QUALIFIER?

Description : WHAT IS A KEY FLEXFIELD QUALIFIER?

Last Answer : - A qualifier is a label attached to a particular key flexfield segment so it can be located by the application requiring its information. A key flexfield qualifier can be of 2 types: · Flexfield qualifiers identify a segment in a flexfield. · Segment qualifiers identify a value set in a segment.

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Description : KEY AND DEXCRIPTIVE FLEXFIELD COMPARISON

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HOW MANY KEY FLEXFIELDS ARE THERE IN ORACLE FINANCIALS?

Description : HOW MANY KEY FLEXFIELDS ARE THERE IN ORACLE FINANCIALS?

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What are partial, alternate,, artificial, compound and natural key?

Description : What are partial, alternate,, artificial, compound and natural key?

Last Answer : Partial Key: It is a set of attributes that can uniquely identify weak entities and that are related to same owner entity. It is sometime called as Discriminator. Alternate Key: All Candidate ... create a unique identifier for the construct is known as creating a compound key. Natural Key:

What is Domain-Key Normal Form?

Description : What is Domain-Key Normal Form?

Last Answer : 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.

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

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You want to send a valuable object to a friend. You have a box which is more than large enough to contain the object. You have several locks with keys. The box has a locking ring which is more than large enough to have a lock attached. But your friend does not have the key to any lock that you have. How do you do it? Note that you cannot send a key in an unlocked box, since it might be copied. -Riddles

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Last Answer : Attach a lock to the ring. Send it to her. She attaches her own lock and sends it back. You remove your lock and send it back to her. She removes her lock.

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Description : Mark correct option a) Bill of franking machine used is prepared in form MS10 b) In RMS offices, letter box key should be kept in custody of Sorting Assistant c) Greeting cards are treated as first class ... Label bundle should not contain more than 50 to 60 letters & post cards. e) All of the above

Last Answer : ) All of the above

The Markets and Competitors section of a business plan should contain ____________. A. A statement of the target market. B. The size of each market segment. C. The key characteristics of buyers in each business segment. D. All the above.

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Last Answer : a

Fertilizers contain more than 25% of primary nutrients, e.g. Urea (46%), DAP (18% N and 46% P2O5 ).

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Can u have more than one layout in report

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Is it possible to attach same library to more than one form?

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Last Answer : Yes

Can you have more than one content canvas view attached with a window?

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............. is a combination of two of more attributes used as a primary key A) Composite Key B) Alternate Key C) Candidate Key D) Foreign Key

Description : ............. is a combination of two of more attributes used as a primary key A) Composite Key B) Alternate Key C) Candidate Key D) Foreign Key

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Which statement about bias in social studies sources is true A) most social studies sources are unbiased b)bias most often found in primary sources c) bias often found in secondary sources d) most social studies sources contain some bias?

Description : Which statement about bias in social studies sources is true A) most social studies sources are unbiased b)bias most often found in primary sources c) bias often found in secondary sources d) most social studies sources contain some bias?

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