MCA PU 1st Sem and 3rd Sem 2022 Question papers

MCA PU 2022 1st Sem Question papers Available :-> *link*

MCA PU 2022 3rd Sem Question papers Available :-> *link*

Learn C# from Basics to advanced

Go to this page and explore C# 

https://mcaputreasure.blogspot.com/p/c-from-basics.html

For Program Basics examples go to this *page*

Update

 Software Engineering Books are now available in Bookstore Server , check out and enjoy!

How to install JDK without Oracle Account

To download any JRE or JDK from the Oracle download page without signing in, go to the downloads page for the version you want (such as https://www.oracle.com/java/technologies/jdk12-downloads.html) and click on the Download link of your choice.

When a window pops up saying you need to accept the license agreement, check the box that says you agree. But instead of clicking on the green Download link (which will send you to the login page), right-click the download link and select Copy Link Location.
NOTE: If clicking Download doesn't show a box and takes you straight to the login page instead, you will need to clear your cookies on the Java website (or open in incognito mode).
Paste the copied link into a text editor like Notepad. You'll see the link points to something like oracle.com/webapps/redirect/signon, but it has a query attached that starts with "nexturl=". The URL that follows nexturl= is the actual link that will download the file to your computer.

If you want to download any JRE or JDK without signing into Oracle, go to the downloads page for the version you want (such as https://www.oracle.com/java/technologies/jdk12-downloads.html) and right-click on the Download link of your choice. Select "Copy Link Location" and then paste it into a text editor like Notepad.

NOTE: you may need to change the otn in the path to otn-pub as described below. 

For example:- 

See this link :-

https://www.oracle.com/webapps/redirect/signon?nexturl=https://download.oracle.com/otn/java/jdk/8u291-b10/d7fc238d0cbf4b0dac67be84580cfb4b/jdk-8u291-windows-x64.exe

Modify this link to like this remove ""https://www.oracle.com/webapps/redirect/signon?nexturl="" and change otn to otn-pub as shown below :-

Step 1 :-https://www.oracle.com/webapps/redirect/signon?nexturl=https://download.oracle.com/otn/java/jdk/8u291-b10/d7fc238d0cbf4b0dac67be84580cfb4b/jdk-8u291-windows-x64.exe

Step 2 :- 

https://download.oracle.com/otn-pub/java/jdk/8u291-b10/d7fc238d0cbf4b0dac67be84580cfb4b/jdk-8u291-windows-x64.exe

How to install JDK proper for Windows x32 or x64

Step 1: 

Download JDK for Windows in the given links:

*** JDK 11 Setup x64 link *** (LTS)

*** JDK 16 Setup link ***  (Latest Version)

Link is available till 20th April....

Step 2:

Now follow these steps:-

Open this file :-

Step 3:-

Make sure you give recommended default path otherwise you may face environment variables problem as shown in the picture:-

Also make sure you have enough space to install this JDK 

****Next Step*****

How to download these popup books offline

 Follow these steps:-

Step 1:- 

Step 2:- 

MCA Panjab University DBMS Old Question paper solved

ANSWER KEY OF DBMS Old Question paper:-

Unit - 1

Q1 a):- Three level architecture of DBMS with diagram.

How this leads to data independence explained below:-

The three-schema architecture can be used to further explain the concept of data independence, which can be defined as the capacity to change the schema at one level of a database system without having to change the schema at the next higher level. We can define two types of data independence:

                    Logical data independence is the capacity to change the conceptual schema without having to change external schemas or application programs. We may change the conceptual schema to expand the database (by adding a record type or data item), to change constraints, or to reduce the database (by removing a record type or data item). In the last case, external schemas that refer only to the remaining data should not be affected. For example, the external schema of Figure 1.5(a) should not be affected by changing the GRADE_REPORT file (or record type) shown in Figure 1.2 into the one shown in Figure 1.6(a). Only the view definition and the mappings need to be changed in a DBMS that supports logical data independence. After the conceptual schema undergoes a logical reorganization, application pro-grams that reference the external schema constructs must work as before.

Changes to constraints can be applied to the conceptual schema without affecting the external schemas or application programs. 

                                                    Physical data independence is the capacity to change the internal schema without having to change the conceptual schema. Hence, the external schemas need not be changed as well. Changes to the internal schema may be needed because some physical files were reorganized—for example, by creating additional access structures—to improve the performance of retrieval or update. If the same data as before remains in the database, we should not have to change the conceptual schema. For example, providing an access path to improve retrieval speed of section records (Figure 1.2) by semester and year should not require a query such as list all sections offered in fall 2008 to be changed, although the query would be executed more efficiently by the DBMS by utilizing the new access path.

Generally, physical data independence exists in most databases and file environments where physical details such as the exact location of data on disk, and hard-ware details of storage encoding, placement, compression, splitting, merging of records, and so on are hidden from the user. Applications remain unaware of these details. On the other hand, logical data independence is harder to achieve because it allows structural and constraint changes without affecting application programs—a much stricter requirement. 

Whenever we have a multiple-level DBMS, its catalog must be expanded to include information on how to map requests and data among the various levels. The DBMS uses additional software to accomplish these mappings by referring to the mapping information in the catalog. Data independence occurs because when the schema is changed at some level, the schema at the next higher level remains unchanged; only the mapping between the two levels is changed. Hence, application programs refer-ring to the higher-level schema need not be changed.

The three-schema architecture can make it easier to achieve true data independence, both physical and logical. However, the two levels of mappings create an overhead during compilation or execution of a query or program, leading to inefficiencies in the DBMS. Because of this, few DBMSs have implemented the full three-schema architecture.

 

Q b):- Hierarchical DB model 

Advantages

• Have many different structures and forms.
• Structures data in an upside-down tree. (Simplifies data overview)
• Manages large amounts of data.
• Express the relationships between information.
• Many children per parent.
• Distribute data in terms of relationships.
• Improve data sharing.

Disadvantages

• One parent per child.
• Complex (users require physical representation of database)
• Navigation system is complex.
• Data must be organized in a hierarchical way without compromising the information.
• Lack structural independence.
• Many too many relationships not supported.
• Data independence.

           Network Model

ADVANTAGES OF NETWORK MODEL-

The major advantage of network model are-

1.) Conceptual simplicity-Just like the hierarchical model,the network model is also conceptually simple and easy to design.

2.) Capability to handle more relationship types-The network model can handle the one to many and many to many relationships which is real help in modeling the real life situations.

3.) Ease of data access-The data access is easier and flexible than the hierarchical model.

4.) Data integrity- The network model does not allow a member to exist without an owner.

5.) Data independence- The network model is better than the hierarchical model in isolating the programs from the complex physical storage details.

6.) Database standards

DIS-ADVANTAGE OF NETWORK MODEL-

1.) System complexity- All the records are maintained using pointers and hence the whole database structure becomes very complex.

2.) Operational Anomalies- The insertion,deletion and updating operations of any record require large number of pointers adjustments.

3.) Absence of structural independence-structural changes to the database is very difficult.

 

Q2 a):- E-R diagram Coming Soon

b) :- Database Management System

        Components of DBMS 

 

 Unit - 2

Q3 a):- Relational Data Model

RELATIONAL DATA MODEL

The relational data model was introduced in 1970 by Edgar F. Codd. He worked for IBM. All data is represented as simple tabular data structures which the user can access through a high-level non-procedural language. In 1974 IBM proposed a new high-level non-procedural language – SEQUEL (renamed into SQL in 1990).

Advantages

• Structured independence is promoted.
• Users do not have to know the physical representation of the database.
• Use of SQL language to access data.
• Easier database design.
• Tabular view improves simplicity.
• Support large amounts of data.
• Data independence.
• Multi-level relationships between data sets
• No need to predefined data relationships.

Disadvantages

• Data anomalies.
• People need training if they want to use the system effectively and efficiently.

Q3 b):- 

• Index - Sequential Files
• Serial File :-

  A serial file is a type of file containing information, which is recorded in the file in the order it occurred. It can also contain files, in which case the files information would be listed in the order they were saved in the serial file. The information or files are essentially recorded in chronological order. New information is appended, or recorded, at the end of the serial file only. There are also no subsets or directories of information in the file.

  Serial files are usually stored in the computer's internal memory, but they could be stored on a disk as well. When a computer reads a serial file, it starts at the beginning and reads the information sequentially. Serial files are beneficial due to the speed and ease at which a computer can read them.
  

• Direct File 
• Sequential File system

  b) :- Data integrity

Referential integrity

Referential integrity refers to the series of processes that make sure data is stored and used uniformly. Rules embedded into the database’s structure about how foreign keys are used ensure that only appropriate changes, additions, or deletions of data occur. Rules may include constraints that eliminate the entry of duplicate data, guarantee that data is accurate, and/or disallow the entry of data that doesn’t apply.

Referential Integrity

Referential integrity ensures that a value in one table references an existing value in another table. The rule of referential integrity states that the value of a foreign key must be within the domain of its related primary key, or it must be null. A domain is the set of valid values for any column.

Foreign keys—table columns that establish links from one table (the master, or referenced table) to another (the detail, or referencing table)—are the implementation of a one-to-many (1:M) relationship between two tables. A foreign key (a column in the referencing table) must always have a corresponding primary key, which is a column having the same data type and length on the referenced side of the relationship. The domain of a foreign key can't fall outside the domain of its corresponding primary key. The domain must be the same, or the foreign key can be null.

A foreign-key value of null signifies an independent, or non-identifying, 1:M relationship. (See "The Foreign Key," August 1999, for an explanation of dependency in 1:M relationships.) In an independent 1:M relationship, a row in the referencing table can exist without a related row in the referenced table. Therefore, you don't need a foreign key value.

In a dependent (identifying) relationship, every row in the referencing table must have a related row in the referenced table. You must enforce a dependent 1:M relationship in the database. You enforce this rule by declaring a foreign-key reference at the time of table creation (in the CREATE TABLE or ALTER TABLE command) or through triggers. Declaring a reference at the time of table creation is known as declarative referential integrity (DRI). Although DRI code executes faster than trigger code, both schemes monitor and maintain referential data integrity. You can't insert into the referencing table a foreign-key value that doesn't already exist in the referenced table. Listing 2 is an example of DRI: The pub_id column references the primary key column of a table called Publishers.

 

Domain integrity

Domain integrity is the collection of processes that ensure the accuracy of each piece of data in a domain. In this context, a domain is a set of acceptable values that a column is allowed to contain. It can include constraints and other measures that limit the format, type, and amount of data entered.

Domain integrity ensures that all the data items in a column fall within a defined set of valid values. Each column in a table has a defined set of values, such as the set of all numbers for Pubs..zip (five-digit), the set of all character strings for Pubs..au_lname, and the set of all dates for Sales..ord_date. When you limit the value assigned to an instance of that column (an attribute), you are enforcing domain integrity. Domain integrity enforcement can be as simple as choosing the correct data type and length for a column. In the Pubs database's titles table, the column PubDate has a datetime data type and is not nullable. The creator of the titles table chose a non-null condition and a datetime data type for this column. This choice ensures that a value is always present for the PubDate column, and that the value is a valid date, such as 11/22/99. In this way, the creator put in place some controls to maintain domain integrity.

Q4 b):- Functional Dependencies are constraints of set of legal relation in a database

 Unit - 3

   

Decision Table

Decision Table

A decision table is a graphical method for explaining the logic of making decision in tabular format.

It is a set of conditions + set of actions and different combinations of decisions.

“It is a matrix representation of logic of decisions which specify the possible conditions for decision and resulting actions.”

The decision table is divided into two parts:

1.    Condition

2.    Action

1.    Condition:

The condition part specifies all conditions that are applied to the inputted data. It is also divided into two parts à

                                                       i.            Condition Stub:-

It describes the conditions that exist in the program logic.

                                                     ii.            Condition Entry:-

It provides answers to questions asked in the condition asked in the condition term.

2.    Action:

The action part is subdivided into two parts à

                                                       i.            Action Stub:-

It describes the action to be taken to meet each condition.

                                                     ii.            Action Entry:-

It describes the appropriate action resulting from the answer to the condition in condition entry.

Format:

Table Heading

Decision Rule

Condition Stub

Condition Entry

Action Stub

Action Entry

Advantages of Decision Table

1.    It provides compact representation of decision making process.

2.    It is easier to understand particular path.

3.    It can be changed according to situation.

4.    These are best suited for calculating discounts, commissions or inventory control procedures.

5.    The structure of decision table promotes a logically complete and consistent problem definition.

Disadvantages of Decision Table

1.    It cannot express the complete sequence of operations to solve a problem therefore it may be difficult for the programmer to translate decision table into program.

2.    If there are too many alternatives, it is difficult to list in decision table.

3.    It does not show the flow of logic for the solution to a given problem.

Mathematical Structure in Computer Science

 Here are some links for the subject in MCA:-

Mathematical Structure in Computer Science:-

1. Finite State Machines :

• Link 1
• Link 2  <- (With Easy Examples here) 
• Link 3

More Stuff Coming Soon

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