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Discuss the general characteristics of advanced database applications
large number of data types Less portable example: CAD, CAM, OIS Real-time access and large number of users, For example: CAD, Network Management System Large volume of data, For example: GIS, CAM
large number of data types
Less portable example: CAD, CAM, OIS
Real-time access and large number of users, For example: CAD, Network Management System
Large volume of data, For example: GIS, CAM
See lessAdvantage and Disadvantage of Trigger
Advantages: Elimination of redundant code Simplifying modifications Increased security Improved integrity Improved processing power Good fit with the client-server architecture Disadvantage: Performance Overhead Complexity Hidden functionality Cascading effects Cannot be scheduled
Advantages:
Disadvantage:
Find a quadratic polynomial, the sum and product of whose zeroes are – 3 and 2, respectively.
Let the polynomial be $P(x) = ax^2 + bx + c$ Given Sum of Zeroes = -3 So, $-\frac{b}{a} = -3$ assuming a = 1 then, $-\frac{b}{1} = -3$ $\Rightarrow -b = -3$ $\Rightarrow b = 3$ Given Product of Zeroes = 2 So, $\frac{c}{a} = 2$ assuming a = 1 then, $\frac{c}{1} = 2$ $\Rightarrow c = 2$ Now a =Read more
Let the polynomial be
Given Sum of Zeroes = -3
So,
assuming a = 1 then,
Given Product of Zeroes = 2
So,
assuming a = 1 then,
Now a = 1, b = 3 and c = 2
Hence the required quadratic polynomial =
=
=
See lessShow that 3√2 is irrational.
Show that 5 – √3 is irrational.
Use Euclid’s division lemma to show that the square of any positive integer is either of the form 3m or 3m + 1 for some integer m.
Use Euclid’s division lemma to show that the cube of any positive integer is of the form 9m,9m+1or9m+8
Consider the numbers , where n is a natural number. Check whether there is any value of n for which ends with the digit zero.
5. Check whether 6^n can end with the digit 0 for any natural number n.
Find the LCM and HCF of the following integers by applying the prime factorisation method of 12,15 and 21
An army contingent of 616 members is to march behind an army band of 32 members in a parade. The two groups are to march in the same number of columns. What is the maximum number of columns in which they can march?
Sol:- Maximum number of columns = HCF(32, 616) By Euclid's division method, 616 = 32 × 19 + 8 32 = 8 × 4 + 0 ∴ HCF(32, 616) = 8 Maximum number of columns = 8
Sol:-
Maximum number of columns = HCF(32, 616)
By Euclid’s division method,
616 = 32 × 19 + 8
32 = 8 × 4 + 0
∴ HCF(32, 616) = 8
Maximum number of columns = 8
See lessExplain why 7×11×13+13 and 7×6×5×4×3×2×1+5 are composite numbers
Given that HCF (306, 657) = 9, find LCM (306, 657)
See less
Find the zeroes of the polynomial x² – 3 and verify the relationship between the zeroes and the coefficients.
Recall the identity a² – b² =(a – b)(a + b). Using it,we can write: x²-3=(x-√3)(x+√3) So the value of x²-3 is zero when x=√3 or x=-√3 Therefore, the zeroes of x²-3 are √3 and -√3 Sum of zeroes =√3-√3=-3/1=-(Coefficient of x)/(Coefficient of x²) Product of zeroes =(√3)(-√3)=(-3)/1 =(Constant tRead more
Show that any positive odd integer is of the form 6q+1, or 6q+3, or 6q+5, where q is some integer.
Sol:- Let us start with taking a, where a is a positive odd integer. We apply the division algorithm with a and b = 6. Since 0 ≤ r < 6, the possible remainders are 0, 1, 2 , 3, 4 and 5. That is, a can be 6q, or 6q + 1, or 6q + 2, or 6q + 3 or 6q + 4 or 6q + 5, where q is the quotient. However, siRead more
Sol:-
Let us start with taking a, where a is a positive odd integer. We apply the division algorithm with a and b = 6.
Since 0 ≤ r < 6, the possible remainders are 0, 1, 2 , 3, 4 and 5.
That is, a can be 6q, or 6q + 1, or 6q + 2, or 6q + 3 or 6q + 4 or 6q + 5, where q is the quotient.
However, since a is odd, a cannot be 6q or 6q + 2 or 6q + 4 (since they are divisible by 2). Therefore, any odd integer is of the form 6q + 1 or 6q + 3 or 6q + 5.
See lessA sweetseller has 420 kaju barfis and 130 badam barfis. She wants to stack them in such a way that each stack has the same number, and they take up the least area of the tray. What is the maximum number of barfis that can be placed in each stack for this purpose?
Sol:- This can be done by trial and error. But to do it systematically, we find HCF (420, 130). Then this number will give the maximum number of barfis in each stack and the number of stacks will then be the least. The area of the tray that is used up will be the least. Now, let us use Euclid’s algoRead more
Sol:-
This can be done by trial and error. But to do it systematically, we find HCF (420, 130). Then this number will give the maximum number of barfis in each stack and the number of stacks will then be the least. The area of the tray that is used up will be the least.
Now, let us use Euclid’s algorithm to find their HCF. We have :
420= 130×3+30
130= 30×4+10
30= 10×3+0
So, the HCF of 420 and 130 is 10.
See lessTherefore, the sweetseller can make stacks of 10 for both kinds of barfi.
Show that any positive odd integer is of the form 4q + 1 or 4q + 3, where q is some integer.
Sol:- Let us start with taking a, where a is a positive odd integer. We apply the division algorithm with a and b = 4. Since 0 ≤ r < 4, the possible remainders are 0, 1, 2 and 3. That is, a can be 4q, or 4q + 1, or 4q + 2, or 4q + 3, where q is the quotient. However, since a is odd, a cannot be 4Read more
Sol:-
Let us start with taking a, where a is a positive odd integer. We apply the division algorithm with a and b = 4.
Since 0 ≤ r < 4, the possible remainders are 0, 1, 2 and 3.
That is, a can be 4q, or 4q + 1, or 4q + 2, or 4q + 3, where q is the quotient.
However, since a is odd, a cannot be 4q or 4q + 2 (since they are both divisible by 2). Therefore, any odd integer is of the form 4q + 1 or 4q + 3.
See lessFind the LCM and HCF of 6 and 20 by the prime factorisation method.
Sol:-
Sol:-
See lesswhat are Triggers?
A trigger is an SQL statement that is executed automatically by the DBMS as a side effect of a modification - the triggering event - to a named table. The act of executing a trigger is sometimes known as firing the trigger. Some Use Cases : • validating input data and maintaining complex integrity conRead more
A trigger is an SQL statement that is executed automatically by the DBMS as a side effect of a modification – the triggering event – to a named table.
The act of executing a trigger is sometimes known as firing the trigger.
Some Use Cases :
• validating input data and maintaining complex integrity constraints.
• supporting alerts that action needs to be taken when a table is updated in some way.
• refreshing derived attributes after an update operation.
• maintaining audit information, by recording the changes made, and by whom.
• supporting replication.
The basic format of the CREATE TRIGGER statement is as follows:
CREATE TRIGGER TriggerName
BEFORE | AFTER | INSTEAD OF <triggerEvent> ON <TableName>
[REFERENCING <oldOrNewValuesAliasList>]
[FOR EACH {ROW | STATEMENT}]
[WHEN (triggerCondition)]
<triggerBody>
• Triggering events include insertion, deletion, and update of rows in a table. In the latter case only, a triggering event can also be set to cover specific named columns of a table.
• A trigger has an associated timing of either BEFORE, AFTER, or INSTEAD OF.
• A BEFORE trigger is fired before the associated event occurs
• An AFTER trigger is fired after the associated event occurs
• An INSTEAD OF trigger is fired in place of the trigger event.
Three different types of Triggers
Row-Level Triggers (FOR EACH ROW) • execute for each row of the table that is affected by the triggering event
See lessStatement-Level Triggers (FOR EACH STATEMENT) • execute only once even if multiple rows are affected by the triggering event.
Cascading Triggers .Triggers can also activate themselves one after the other.
This can happen when the trigger action makes a change to the database that has the effect of causing another event that has a trigger associated with it to fire.
How is a procedure different from a function?
Both can modify and return data passed to them as a parameter, but a function can only return a single value to the caller.
Both can modify and return data passed to them as a parameter, but a function can only return a single value to the caller.
See lessWhat are cursors, exceptions, stored procedures
Cursor- A SELECT statement can be used if the query returns exactly one row. To handle a query that can return an arbitrary number of rows, PL/SQL uses cursors to allow the rows of a query result to be accessed one at a time. The cursor can be advanced by one to access the next row. A cursor must beRead more
Cursor- A SELECT statement can be used if the query returns exactly one row. To handle a query that can return an arbitrary number of rows, PL/SQL uses cursors to allow the rows of a query result to be accessed one at a time. The cursor can be advanced by one to access the next row.
A cursor must be
• declared and opened before it can be used
• closed to deactivate it after it is no longer required
Once the cursor has been opened, the rows of the query result can be retrieved one at a time using a FETCH statement.
Exceptions:
An exception is an identifier in PL/SQL raised during the execution of a block that terminates its main body of actions, although some final actions can be performed.
An exception can be raised automatically or explicitly using the RAISE statement
To handle raised exceptions, separate routines called exception handlers are specified.
The exception handler itself is defined at the end of the PL/SQL block.
Stored Procedures:
Sub program in PL/SQL that can take parameter and be invoked. They can modify and return data passed to them as a parameter.
A stored procedure is a subroutine available to applications that access a relational database management system (RDBMS). Such procedures are stored in the database data dictionary.
Typical uses for stored procedures include data-validation (integrated into the database) or access-control mechanisms.
See lessWhat led to the introduction of PL/SQL and SQL/PSM?
Initial versions of SQL have been computationally incomplete (without programming constructs). Later versions of SQL could be embedded in a high-level programming language, but produced an impedance mismatch, because of the mixing of different programming paradigms. SQL/PSM: SQL has been extendedRead more
Initial versions of SQL have been computationally incomplete (without programming constructs). Later versions of SQL could be embedded in a high-level programming language, but produced an impedance mismatch, because of the mixing of different programming paradigms.
SQL/PSM:
SQL has been extended to a full programming language
The extensions are known as SQL/PSM (Persistent Stored Modules)
PL/SQL: PL/SQL (Procedural Language SQL) is the Oracle version of an SQL programming language and has concepts similar to modern programming languages, such as variable and constant declarations, control structures, exception handling, and modularization.
See lessConcepts of the (Extended) Entity Relationship Model
The Extended Entity-Relationship Model is a more complex and high-level model that extends an E-R diagram to include more types of abstraction, and to more clearly express constraints. All of the concepts contained within an E-R diagram are included in the E-R model, along with additional concepts tRead more
The Extended Entity-Relationship Model is a more complex and high-level model that extends an E-R diagram to include more types of abstraction, and to more clearly express constraints. All of the concepts contained within an E-R diagram are included in the E-R model, along with additional concepts that cover more semantic information.
These additional concepts include:- generalization/specialization, union, inheritance, and subclass/super class.
Relation: A relation is a table with columns and rows
Attribute: An attribute is a named column of a relation.
Domain: A domain is the set of allowable values for one or more attributes.
Primary key: the candidate key that is selected to identify tuples uniquely within the relation.
Foreign key: an attribute, or set of attributes, within one relation that matches the candidate key of some (possibly the same) relation.
Integrity constraints:
Domain integrity: Describes the restriction on the set of allowed values for an attribute.
Entity Integrity: No attribute of a primary key can be null.
Referential Integrity: If a foreign key exists in a relation, either the foreign key value must match a candidate key value of some tuple in its home relation or the foreign key value must be wholly null.
Referential integrity is a relational database concept, which states that table relationships must always be consistent. In other words, any foreign key field must agree with the primary key that is referenced by the foreign key.
Views: The dynamic result of one or more relational operations operating on the base relations to produce another relation. A view is a virtual relation that does not necessarily exist in the Database but can be produced upon request by a particular user, at the time of request.
Null represents a value for an attribute that is currently unknown or is not applicable for this tuple.
See lesswhat is Data Independence ?
Data Independence A major objective for the three-level architecture is to provide data independence, which means that upper levels are unaffected by changes to lower levels. There are two kinds of data independence: Logical Data Independence: The immunity of the external schema to changes in theRead more
Data Independence
A major objective for the three-level architecture is to provide data independence, which means that upper levels are unaffected by changes to lower levels.
There are two kinds of data independence:
Logical Data Independence: The immunity of the external schema to changes in the conceptual schema
Physical Data Independence: The immunity of the conceptual schema to changes in the internal schema
See lesswhat is Three-Level Architecture?
Three-Level Architecture:- External Level: The users’ view of the database describes that part of the database that is relevant to each user Conceptual Level: The logical view of the database describes what data is stored in the database and the relationships among the data. Internal Level: ThRead more
Three-Level Architecture:-
External Level: The users’ view of the database describes that part of the database that is relevant to each user
Conceptual Level: The logical view of the database describes what data is stored in the database and the relationships among the data.
Internal Level: The physical representation of the database on the computer describes how the data is stored in the database
See less