"Databases"

🔷 What is a Database?

A database is an organized collection of data that is stored electronically and can be accessed, managed, and updated efficiently.

🔷 Purpose of a Database

Store large amounts of data systematically.
Retrieve data quickly and accurately.
Manage data with relationships (like between customers and orders).
Maintain integrity and consistency of data.
Enable multi-user access with security controls.

🔷 Types of Databases

Type	Description	Example
Relational	Stores data in tables with rows and columns	SQL Server, MySQL, Oracle
NoSQL	Stores unstructured or semi-structured data	MongoDB, Cassandra
In-Memory	Data stored in RAM for fast access	Redis
Cloud-based	Databases hosted on cloud platforms	AWS RDS, Azure SQL Database

🔷 Key Components of a Relational Database

Component	Description
Table	A set of rows and columns (like an Excel sheet)
Record (Row)	A single data entry in a table
Field (Column)	Represents one attribute of data (e.g., Name, Age)
Primary Key	Uniquely identifies each record in a table
Foreign Key	Links one table to another (for relationships)

🔷 Common Database Terms

SQL (Structured Query Language): Used to query and manipulate data.
CRUD Operations:
Create: Insert new records.
Read: Retrieve data.
Update: Modify existing data.
Delete: Remove records.
Normalization: Organizing data to reduce redundancy.

🔷 How .NET Interacts with Databases

.NET applications use ADO.NET to connect to databases.
Commonly used databases with .NET:
Microsoft SQL Server
SQLite
MySQL
Oracle

🔷 Example Table: `Students`

StudentID (PK)	Name	Age	Course
1	Rahul	20	BCA
2	Priya	21	B.Sc. IT

🔷 Benefits of Using Databases in Applications

Centralized data storage
Improved performance and security
Easy backup and recovery
Data sharing among multiple users

✅ Summary

Feature	Description
Definition	Structured data storage system
Example Systems	SQL Server, MySQL, MongoDB
Core Operations	CRUD (Create, Read, Update, Delete)
.NET Integration	Via ADO.NET or Entity Framework

"Database Transaction"

🔷 What is a Database Transaction?

A database transaction is a sequence of one or more SQL operations that are executed as a single unit of work.

All operations in a transaction must either complete successfully together (commit) or fail together (rollback).
A transaction ensures data consistency, accuracy, and integrity.

🔷 Properties of Transactions – ACID

Property	Description
A – Atomicity	All operations in a transaction are treated as a single unit. Either all succeed or none are applied.
C – Consistency	The database moves from one valid state to another after a successful transaction.
I – Isolation	Transactions are independent and do not interfere with each other.
D – Durability	Once a transaction is committed, changes are permanent even in case of a system failure.

🔷 Example Scenario

Imagine transferring ₹1000 from Account A to Account B:

Subtract ₹1000 from Account A.
Add ₹1000 to Account B.

If only the first step happens and the second fails — the money is lost. Using a transaction, both steps will succeed or both will fail.

🔷 Transaction in SQL (Basic Syntax)

BEGIN TRANSACTION;
UPDATE Accounts SET Balance = Balance - 1000 WHERE AccountID = 'A';
UPDATE Accounts SET Balance = Balance + 1000 WHERE AccountID = 'B';
COMMIT;

If there's an error:

ROLLBACK;

🔷 Using Transactions in ADO.NET (VB.NET Example)

Dim con As New SqlConnection("Your_Connection_String")
con.Open()

Dim transaction As SqlTransaction = con.BeginTransaction()
Dim cmd As New SqlCommand()
cmd.Connection = con
cmd.Transaction = transaction

Try
    ' First query
    cmd.CommandText = "UPDATE Accounts SET Balance = Balance - 1000 WHERE AccountID = 'A'"
    cmd.ExecuteNonQuery()

    ' Second query
    cmd.CommandText = "UPDATE Accounts SET Balance = Balance + 1000 WHERE AccountID = 'B'"
    cmd.ExecuteNonQuery()

    ' Commit if both succeed
    transaction.Commit()
    MessageBox.Show("Transaction Successful")

Catch ex As Exception
    ' Rollback if error occurs
    transaction.Rollback()
    MessageBox.Show("Transaction Failed: " & ex.Message)
Finally
    con.Close()
End Try

🔷 Benefits of Using Transactions

Ensures data accuracy and reliability
Protects against partial updates or system crashes
Maintains business rules and logic

✅ Summary

Feature	Description
Transaction	Group of SQL statements that run as one unit
ACID Properties	Guarantees integrity and reliability of data
ADO.NET Usage	Begin, Commit, and Rollback via `SqlTransaction`
Real-Life Use Cases	Bank transfers, order processing, reservation systems

"ADO.NET"

🔷 What is ADO.NET?

ADO.NET (ActiveX Data Objects for .NET) is a set of classes in the .NET Framework used to interact with databases and other data sources like XML.

It is part of the System.Data namespace.
Allows your .NET applications to connect, retrieve, insert, update, and delete data from a database.
ADO.NET supports both connected and disconnected data access models.

🔷 Key Features of ADO.NET

Feature	Description
Data Access	Provides access to SQL Server, Oracle, MySQL, XML, etc.
Disconnected Architecture	Uses DataSet to work with data offline (not constantly connected)
Scalability	Efficient for large-scale enterprise applications
Performance	Uses optimized data providers and minimal memory usage
Interoperability	Can work with XML and Web Services

🔷 ADO.NET Architecture

ADO.NET has two main components:

Connected Architecture
Works directly with the database using a Connection.
Uses Command, DataReader to execute SQL queries and retrieve results.
Disconnected Architecture
Uses DataSet, DataTable, DataAdapter.
Data is fetched and stored in memory, and the connection is closed.
Useful for minimizing open database connections.

🔷 Key ADO.NET Objects

Object	Description
Connection	Establishes a link between the application and the database.
Command	Executes SQL queries (SELECT, INSERT, UPDATE, DELETE).
DataReader	Reads data in a fast, forward-only, read-only way (connected).
DataAdapter	Fills data into a DataSet (disconnected mode).
DataSet	In-memory representation of data (tables, rows, relations).
DataTable	Represents a single table of in-memory data.
SqlTransaction	Manages transactions (commit or rollback SQL commands).

🔷 Example: Simple ADO.NET Flow

Imports System.Data.SqlClient

Dim con As New SqlConnection("Your_Connection_String")
Dim cmd As New SqlCommand("SELECT * FROM Students", con)
con.Open()

Dim reader As SqlDataReader = cmd.ExecuteReader()

While reader.Read()
    Console.WriteLine(reader("Name"))
End While

reader.Close()
con.Close()

🔷 Connected vs Disconnected Model

Feature	Connected Model	Disconnected Model
Main Objects	Connection, Command, DataReader	DataSet, DataTable, DataAdapter
Usage	Real-time, fast reading	Offline processing
Performance	High for small, fast operations	Efficient for large/batch tasks
Flexibility	Less flexible	Highly flexible

🔷 Advantages of ADO.NET

Supports both real-time and offline data processing
Works well with various databases
Can use strongly typed data access
Ideal for enterprise-level applications

✅ Summary

Topic	Key Points
What is ADO.NET	.NET technology for accessing and manipulating databases
Models Supported	Connected (DataReader), Disconnected (DataSet)
Main Classes	SqlConnection, SqlCommand, SqlDataReader, SqlDataAdapter
Use Cases	Data retrieval, updates, transactions, reporting, etc.

"DataSet in ADO.NET"

🔷 What is a DataSet?

A DataSet is an in-memory cache of data retrieved from a database. It stores data in a disconnected mode, meaning once data is fetched, the connection to the database can be closed.

It is part of the System.Data namespace.
Can hold multiple DataTables, relationships, and constraints.

🔷 Key Features of DataSet

Feature	Description
Disconnected	Works offline, no need for an open database connection.
Multiple Tables	Can hold multiple tables and define relationships between them.
XML Support	Data can be read from or written to XML.
Relational View	Maintains relationships like primary keys, foreign keys.
Data Manipulation	Supports editing, adding, deleting, and updating rows.

🔷 DataSet Structure

A DataSet contains:

DataTable(s): Individual tables with rows and columns.
DataRelation(s): Define relationships between tables (like foreign keys).
Constraints: Ensure data integrity (e.g., uniqueness, primary key).

DataSet
├── DataTable: Students
├── DataTable: Courses
└── DataRelation: Students ↔ Courses

🔷 Basic Syntax (VB.NET Example)

Imports System.Data
Imports System.Data.SqlClient

Dim con As New SqlConnection("Your_Connection_String")
Dim da As New SqlDataAdapter("SELECT * FROM Students", con)
Dim ds As New DataSet()

' Fill DataSet with data from database
da.Fill(ds, "Students")

' Access data
Dim dt As DataTable = ds.Tables("Students")

For Each row As DataRow In dt.Rows
    Console.WriteLine(row("Name"))
Next

🔷 Working with DataSet

Task	Code Example
Create a DataSet	`Dim ds As New DataSet()`
Add a DataTable	`ds.Tables.Add(New DataTable("Employees"))`
Access a DataTable	`ds.Tables("Employees")`
Read data from rows	`row("ColumnName")`
Write to XML	`ds.WriteXml("data.xml")`
Read from XML	`ds.ReadXml("data.xml")`

🔷 Differences: DataSet vs DataReader

Feature	DataSet	DataReader
Connection	Disconnected	Connected
Flexibility	High – multiple tables, XML, etc.	Low – forward-only
Performance	Slower (for large data)	Faster
Use Case	Batch processing, offline operations	Fast, read-only access

🔷 Advantages of DataSet

No need to keep the connection open after fetching data.
Supports complex data operations (like table relations).
Works well with XML for import/export.
Good for Windows Forms and reporting apps.

✅ Summary

Property	Description
Class	`System.Data.DataSet`
Use	Offline data storage and manipulation
Contains	DataTables, DataRelations, Constraints
Common Methods	`.Tables`, `.WriteXml()`, `.ReadXml()`, `.Clear()`

"Connecting to a Database"

🔷 What is a Database Connection?

A database connection is a link between your .NET application and the database server (e.g., SQL Server). It allows your program to send queries, fetch data, and perform operations like insert, update, or delete.

🔷 Key Object: `SqlConnection`

Provided by the System.Data.SqlClient namespace.
Used to open and manage the connection to a SQL Server database.

🔷 Basic Steps to Connect

Import the Namespace

vb.net Imports System.Data.SqlClient

Declare Connection String A string that holds info to locate and connect to the database.

vb.net Dim conStr As String = "Data Source=SERVER_NAME;Initial Catalog=DB_NAME;Integrated Security=True"

Or using SQL login:

vb.net Dim conStr As String = "Data Source=SERVER_NAME;Initial Catalog=DB_NAME;User ID=yourUsername;Password=yourPassword"

Create Connection Object

vb.net Dim con As New SqlConnection(conStr)

Open the Connection

vb.net con.Open()

Perform Operations (Select, Insert, etc.)
Close the Connection

vb.net con.Close()

🔷 Example: Connecting to SQL Server and Retrieving Data

Imports System.Data.SqlClient

Module Module1
    Sub Main()
        Dim conStr As String = "Data Source=.\SQLEXPRESS;Initial Catalog=StudentDB;Integrated Security=True"
        Dim con As New SqlConnection(conStr)

        Try
            con.Open()
            Console.WriteLine("Connection Successful!")

            Dim cmd As New SqlCommand("SELECT * FROM Students", con)
            Dim reader As SqlDataReader = cmd.ExecuteReader()

            While reader.Read()
                Console.WriteLine("Name: " & reader("Name"))
            End While

            reader.Close()

        Catch ex As Exception
            Console.WriteLine("Error: " & ex.Message)
        Finally
            con.Close()
        End Try
    End Sub
End Module

🔷 Important Properties and Methods

Property / Method	Description
`.Open()`	Opens the database connection
`.Close()`	Closes the connection
`.State`	Checks the state (Open/Closed) of the connection
`.ConnectionString`	Sets or gets the connection string

🔷 Best Practices

Always close the connection after operations (use Finally block).
Use Using block to ensure automatic disposal of resources.
Avoid hardcoding credentials — use configuration files.

✅ Summary

Concept	Details
Purpose	To link .NET application with the database
Main Class	`SqlConnection` (from `System.Data.SqlClient`)
Process	Define connection string → Open connection → Work → Close
Error Handling	Use Try–Catch–Finally or Using block

“Introduction to Database Programming”

📘 Topic: Introduction to Database Programming

🔷 What is Database Programming?

Database Programming refers to writing code in a programming language (like VB.NET or C#) to interact with a database system (like SQL Server, Oracle, MySQL).

It allows applications to:

Store data permanently
Retrieve data when needed
Update or delete existing records
Perform transactions and data validation

🔷 Why Database Programming is Important?

Reason	Explanation
Data Storage	Store and manage large volumes of structured data
Data Access	Retrieve specific data efficiently
Automation	Automate business logic using stored procedures or queries
User Interaction	Create interactive applications (like student records, billing systems)
Security & Integrity	Ensure controlled access and maintain data accuracy

🔷 Common Operations in Database Programming

Operation	Purpose
Connect	Establish a connection to the database
Insert	Add new records to the database
Select	Retrieve data from the database
Update	Modify existing records
Delete	Remove records

These operations are commonly called CRUD: Create, Read, Update, Delete.

🔷 Tools and Technologies Used

Technology	Purpose
ADO.NET	.NET framework component for data access
SQL	Language for querying and managing databases
Visual Studio	IDE for developing database applications
Database Servers	SQL Server, Oracle, MySQL, etc.

🔷 ADO.NET in Database Programming

ADO.NET is the primary data access technology in .NET. It offers:

Connected model using SqlConnection, SqlCommand, SqlDataReader
Disconnected model using DataSet, DataTable, DataAdapter
Support for transactions, XML, schemas, and data binding

🔷 Example: Simple Database Operation (VB.NET)

Imports System.Data.SqlClient

Dim con As New SqlConnection("Data Source=.;Initial Catalog=SchoolDB;Integrated Security=True")
Dim cmd As New SqlCommand("SELECT * FROM Students", con)

con.Open()
Dim reader As SqlDataReader = cmd.ExecuteReader()

While reader.Read()
    Console.WriteLine(reader("Name"))
End While

reader.Close()
con.Close()

🔷 Advantages of Database Programming

Advantage	Explanation
Centralized Storage	Keeps data in one place
Data Integrity	Ensures accuracy and consistency
Scalability	Handles growing amounts of data
Security	User-level permissions and authentication
Performance	Optimized querying through indexes and keys

✅ Summary

Topic	Key Points
What is it?	Programming to interact with databases
Tools Used	ADO.NET, SQL, Visual Studio, SQL Server, etc.
Operations Performed	CRUD: Create, Read, Update, Delete
Benefits	Secure, fast, reliable, and structured data management

“Microsoft Access 2003”

🔷 What is Microsoft Access 2003?

Microsoft Access 2003 is a relational database management system (RDBMS) developed by Microsoft. It allows users to create, manage, and interact with databases using a graphical interface and SQL.

It is often used for small to medium-sized database applications and integrates well with other Microsoft Office products.

🔷 Features of Microsoft Access 2003

Feature	Description
User-Friendly Interface	Easy-to-use GUI for managing tables, queries, forms, and reports.
Tables	Used to store data in rows and columns.
Queries	Used to filter, sort, and retrieve specific data using SQL or query builder.
Forms	Interface for entering or viewing data in a user-friendly way.
Reports	Used for formatting and printing data summaries or outputs.
Macros	Automates repetitive tasks without coding.
VBA Integration	Supports Visual Basic for Applications for advanced programming.

🔷 Objects in Microsoft Access

Object	Description
Table	Stores raw data. Each table consists of rows (records) and columns (fields).
Query	Used to search and filter data. Can use SQL or query design view.
Form	Data-entry screen for viewing or entering records.
Report	Formats and presents data for printing or sharing.
Macro	Automates tasks (like opening forms, running queries).
Module	Contains VBA code for advanced operations.

🔷 Creating a Simple Database in Access 2003

Open Access 2003
Create a new database → File > New > Blank Database
Create Tables → Design View (define field names and data types)
Set Primary Key → Unique identifier (e.g., StudentID)
Enter Data → Datasheet View
Create Queries → Use Query Wizard or SQL
Design Forms → For data input
Generate Reports → For printable output

🔷 Common Data Types in Access

Data Type	Description
Text	Alphanumeric values (up to 255 chars)
Memo	Long text (more than 255 chars)
Number	Numeric data (integer, decimal, etc.)
Date/Time	Dates and times
Currency	Financial values with formatting
Yes/No	Boolean (True/False)
AutoNumber	Auto-incrementing primary key

🔷 Microsoft Access 2003 with VB.NET / ADO.NET

You can connect an Access 2003 .mdb file with VB.NET using OLEDB.

✅ Example Connection String:

Dim conStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\yourfile.mdb;"
Dim con As New OleDbConnection(conStr)
con.Open()

✅ Required Namespace:

Imports System.Data.OleDb

🔷 Advantages of Access 2003

Advantage	Explanation
Easy to Learn	Ideal for beginners and non-programmers
Office Integration	Works well with Excel, Word, Outlook
Rapid Development	Quick creation of forms, queries, reports
Small Business Friendly	Suitable for small/medium scale applications
Desktop-based	No need for complex server setup

🔷 Limitations

Not ideal for high-traffic multi-user environments.
Limited scalability compared to SQL Server or Oracle.
File-based (prone to corruption in large usage scenarios).

✅ Summary

Topic	Details
What is it?	GUI-based relational database system
Main Objects	Table, Query, Form, Report, Macro, Module
File Format	`.mdb` (Access 2003 format)
Used In	Small business apps, prototyping, data entry systems
Integration	Can be connected to .NET using OleDb

"Database Programming"

🔷 What is Database Programming?

Database Programming involves writing code to interact with a Database Management System (DBMS). It allows software applications to:

Store,
Retrieve,
Update, and
Delete data from databases.

In .NET, this is commonly done using ADO.NET and languages like VB.NET or C#.

🔷 Why is Database Programming Important?

Feature	Purpose
Data Storage	Store structured information permanently
Data Retrieval	Fetch required data efficiently using queries
Data Management	Easily modify and organize records
Integration	Connect with GUI forms, reports, and business logic
Security and Integrity	Enforce rules, permissions, and validations

🔷 Basic Concepts in Database Programming

Database A collection of organized data (e.g., Student Records, Inventory, etc.).
Table Contains data in rows and columns. Each row is a record; each column is a field.
SQL (Structured Query Language) A standard language to query and manipulate databases.
CRUD Operations Common operations in database programming:
Create → Insert new records
Read → Retrieve records
Update → Modify existing records
Delete → Remove records

🔷 Tools Used in Database Programming

Tool/Technology	Purpose
ADO.NET	.NET library to access databases (SQL, Access, etc.)
SQL	Language used to query the database
VB.NET / C#	Programming languages to write database logic
Visual Studio	IDE to design forms and write code
MS SQL Server / Access	Common DBMS used in .NET applications

🔷 ADO.NET in Database Programming

ADO.NET is a key technology in .NET for working with databases. It provides:

Connected Model: Works with live data using SqlConnection, SqlCommand, SqlDataReader.
Disconnected Model: Uses DataSet, DataTable, and DataAdapter to work offline.

🔷 Database Programming Workflow in .NET

Create and Design Database Use tools like MS Access or SQL Server.
Write Connection Code Use SqlConnection or OleDbConnection.
Execute SQL Commands Use SqlCommand to run queries.
Read Data Use SqlDataReader or DataSet to read the results.
Bind Data to Controls Display data in controls like DataGridView, TextBox, etc.
Close Connection Always close the connection to free resources.

🔷 Example Code (VB.NET with SQL Server)

Imports System.Data.SqlClient

Dim conStr As String = "Data Source=.\SQLEXPRESS;Initial Catalog=StudentDB;Integrated Security=True"
Dim con As New SqlConnection(conStr)

con.Open()
Dim cmd As New SqlCommand("SELECT * FROM Students", con)
Dim reader As SqlDataReader = cmd.ExecuteReader()

While reader.Read()
    Console.WriteLine(reader("Name"))
End While

reader.Close()
con.Close()

🔷 Advantages of Database Programming

Advantage	Description
Efficient Data Access	Speeds up storing and retrieving data
Reusability	SQL queries and procedures can be reused
Scalability	Easily manage large volumes of data
Integration	Works well with GUIs, reports, and web applications
Security	Role-based access and data validation mechanisms

✅ Summary

Concept	Description
Definition	Writing code to interact with a database
Core Technologies	SQL, ADO.NET, VB.NET, Visual Studio
Main Operations	CRUD (Create, Read, Update, Delete)
Tools	SQL Server, MS Access, Visual Studio

"Bound Controls"

🔷 What are Bound Controls?

Bound controls are form controls (like TextBox, ComboBox, DataGridView) that are linked to a data source such as a DataSet, DataTable, or a database.

When a bound control is connected, it automatically displays and updates the data from the source without needing manual code for every field.

🔷 Purpose of Bound Controls

To connect UI elements directly to database fields
To display data automatically in forms
To simplify data entry, editing, and viewing
To reduce the amount of code needed for data manipulation

🔷 Examples of Bound Controls

Control Type	Description
TextBox	Displays text from a database field
ComboBox	Displays a list of values from a table/column
DataGridView	Displays entire table records in tabular format
Label	Shows read-only data from a data source

🔷 Types of Data Binding

Type	Description
Simple Binding	Binds a single control to a single field (e.g., TextBox to “Name”)
Complex Binding	Binds a control to multiple fields or a list (e.g., DataGridView to table)

🔷 Example: Binding a TextBox to a Dataset Field

TextBox1.DataBindings.Add("Text", DataSet1.Tables("Students"), "Name")

This binds TextBox1 to the Name column in the Students table.

🔷 Example: Binding a DataGridView to a Table

DataGridView1.DataSource = DataSet1.Tables("Students")

This displays all student records in a grid view.

🔷 Steps to Create Bound Controls in Visual Studio

Create a Data Source (e.g., SQL Server, Access)
Add a DataSet to your project
Design a Form and drag controls (TextBox, DataGridView, etc.)
Set the DataSource and DataBindings in code or using designer
Run the application to view/edit database records

🔷 Advantages of Bound Controls

Advantage	Description
Automatic Sync	Reflects changes instantly between UI and data source
Reduces Code	Eliminates the need for manual data transfer
Easier UI Design	Visual Studio provides drag-and-drop binding tools
Faster Development	Speeds up building data-driven applications

🔷 Disadvantages

Limitation	Explanation
Less Flexibility	Difficult to customize data processing
Performance Issues	May slow down for large datasets
Complex Debugging	Errors may not be as clear as in manual data handling

✅ Summary

Point	Details
What is it?	Control linked to a data source to display/edit values
Examples	TextBox, ComboBox, DataGridView
Binding Types	Simple (single field) and Complex (tables/lists)
Usage	Ideal for data entry forms, dashboards, admin panels

“Basic SQL Statements”

🔷 What is SQL?

SQL (Structured Query Language) is the standard language used to communicate with relational databases. It is used for storing, retrieving, modifying, and deleting data.

🔷 Categories of SQL Statements

Category	Purpose
DML (Data Manipulation Language)	Used to manipulate data (INSERT, SELECT, UPDATE, DELETE)
DDL (Data Definition Language)	Used to define or change structure (CREATE, ALTER, DROP)
DCL (Data Control Language)	Controls access to data (GRANT, REVOKE)
TCL (Transaction Control Language)	Manages transactions (COMMIT, ROLLBACK, SAVEPOINT)

🔹 1. DML – Data Manipulation Language

✅ `SELECT` – Retrieve data

SELECT * FROM Students;
SELECT Name, Age FROM Students WHERE Age > 18;

✅ `INSERT` – Add new record

INSERT INTO Students (Name, Age) VALUES ('John', 20);

✅ `UPDATE` – Modify existing data

UPDATE Students SET Age = 21 WHERE Name = 'John';

✅ `DELETE` – Remove data

DELETE FROM Students WHERE Name = 'John';

🔹 2. DDL – Data Definition Language

✅ `CREATE TABLE` – Define a new table

CREATE TABLE Students (
    StudentID INT PRIMARY KEY,
    Name VARCHAR(50),
    Age INT
);

✅ `ALTER TABLE` – Modify table structure

ALTER TABLE Students ADD Email VARCHAR(100);

✅ `DROP TABLE` – Delete entire table

DROP TABLE Students;

🔹 3. DCL – Data Control Language

✅ `GRANT` – Give permission

GRANT SELECT, INSERT ON Students TO user1;

✅ `REVOKE` – Take back permission

REVOKE INSERT ON Students FROM user1;

🔹 4. TCL – Transaction Control Language

✅ `COMMIT` – Save transaction permanently

COMMIT;

✅ `ROLLBACK` – Undo changes since last commit

ROLLBACK;

✅ `SAVEPOINT` – Set a point to roll back to

SAVEPOINT point1;
ROLLBACK TO point1;

🔷 Common SQL Clauses

Clause	Purpose
WHERE	Filter records based on condition
ORDER BY	Sort records (ASC or DESC)
GROUP BY	Group rows with same values in columns
HAVING	Filter grouped data (like WHERE for GROUP BY)
JOIN	Combine data from two or more tables
LIKE	Search using pattern matching (`LIKE 'A%'`)
IN	Match against multiple values (`IN (10, 20, 30)`)

🔷 Example Queries

👉 Select all students whose age is greater than 18:

SELECT * FROM Students WHERE Age > 18;

👉 Insert a new student record:

INSERT INTO Students (Name, Age) VALUES ('Alice', 22);

👉 Update a student’s name:

UPDATE Students SET Name = 'Alice Smith' WHERE Name = 'Alice';

👉 Delete students younger than 18:

DELETE FROM Students WHERE Age < 18;

✅ Summary

Topic	Description
SQL	Language to work with relational databases
Basic Commands	SELECT, INSERT, UPDATE, DELETE
DDL Commands	CREATE, ALTER, DROP
DCL & TCL	GRANT, REVOKE, COMMIT, ROLLBACK
Useful Clauses	WHERE, ORDER BY, GROUP BY, HAVING, JOIN

LINQ

🔷 What is LINQ?

LINQ stands for Language Integrated Query.
It is a .NET Framework feature that adds native query capabilities directly into C# and VB.NET.
Allows querying collections, databases, XML, and more in a consistent way.
Integrates query syntax inside the programming language itself.

🔷 Why use LINQ?

Benefit	Description
Simplifies Queries	Write complex queries in a readable syntax
Strongly Typed	Checked at compile time, reducing runtime errors
Consistent	Same syntax to query different data sources
Integration	Works with arrays, lists, XML, databases, etc.

🔷 LINQ Query Structure

var result = from item in collection
             where condition
             orderby item.Property
             select item;

from: Source collection
where: Filter condition
orderby: Sort results
select: Specify output

🔷 Types of LINQ

Type	Description
LINQ to Objects	Query in-memory collections like arrays, lists
LINQ to SQL	Query SQL Server databases directly
LINQ to XML	Query and manipulate XML documents
LINQ to Entities	Works with Entity Framework and databases

🔷 Example: LINQ to Objects (C#)

int[] numbers = { 2, 4, 6, 8, 10 };

var evenNumbers = from num in numbers
                  where num % 2 == 0
                  select num;

foreach(var n in evenNumbers)
{
    Console.WriteLine(n);
}

🔷 Benefits in .NET Programming

Reduces boilerplate code for filtering and sorting.
Makes code more declarative and easier to read.
Enables deferred execution — queries run when results are enumerated.
Supports lambda expressions and method syntax for queries.

🔷 Lambda Expression Syntax (Alternate to Query Syntax)

var evenNumbers = numbers.Where(n => n % 2 == 0);

✅ Summary

Point	Description
LINQ	Integrated query syntax in .NET languages
Purpose	Query collections, databases, XML easily
Syntax	Query syntax (`from-where-select`) or method syntax (lambda)
Supports	LINQ to Objects, LINQ to SQL, LINQ to XML, LINQ to Entities

Filtering Data

🔷 What is Filtering Data?

Filtering data means selecting a subset of records from a data source based on specific conditions.
It helps to retrieve only relevant data instead of the entire dataset.
Filtering is essential in databases, collections, and LINQ queries to work efficiently with large data.

🔷 Filtering in SQL

The WHERE clause is used to filter rows in SQL queries.
It specifies conditions that each row must satisfy to be included in the result.

Example:

SELECT * FROM Employees WHERE Department = 'Sales';

This query returns only employees in the Sales department.

🔷 Filtering in ADO.NET

When using ADO.NET, you can filter data in a DataTable using the Select method or DataView.

Using DataTable.Select:

DataRow[] filteredRows = dataTable.Select("Age > 30 AND City = 'Mumbai'");

Using DataView:

DataView dv = new DataView(dataTable);
dv.RowFilter = "Age > 30 AND City = 'Mumbai'";

Both ways allow filtering rows based on expressions similar to SQL WHERE.

🔷 Filtering Data Using LINQ

LINQ provides a natural and type-safe way to filter collections with the where keyword.

Example (LINQ to Objects):

var filteredList = from emp in employees
                   where emp.Age > 30 && emp.City == "Mumbai"
                   select emp;

Using Lambda expressions:

var filteredList = employees.Where(emp => emp.Age > 30 && emp.City == "Mumbai");

🔷 Common Filtering Operators

Operator	Description	Example
`=`	Equal to	`City = 'Mumbai'`
`<>` or `!=`	Not equal to	`Age <> 25`
`>`	Greater than	`Salary > 50000`
`<`	Less than	`Age < 60`
`>=`	Greater than or equal to	`Experience >= 5`
`<=`	Less than or equal to	`Age <= 30`
`LIKE`	Pattern matching (SQL)	`Name LIKE 'A%'`
`IN`	Matches any value in a list	`City IN ('Mumbai', 'Delhi')`
`AND`	Logical AND	Combine multiple conditions
`OR`	Logical OR	Combine multiple conditions
`NOT`	Negates a condition	`NOT City = 'Mumbai'`

🔷 Filtering with Multiple Conditions

Combine multiple conditions with AND and OR to form complex filters.

SQL Example:

SELECT * FROM Employees WHERE Department = 'Sales' AND Age > 30;

LINQ Example:

var filtered = employees.Where(e => e.Department == "Sales" && e.Age > 30);

🔷 Filtering Null or Empty Values

Check for NULL values in SQL:

SELECT * FROM Employees WHERE ManagerID IS NULL;

Check for null or empty strings in C#:

var filtered = employees.Where(e => !string.IsNullOrEmpty(e.Name));

🔷 Benefits of Filtering Data

Benefit	Description
Improves performance	Retrieves only required data, reducing load
Simplifies data handling	Easier to work with smaller, relevant datasets
Enhances user experience	Shows focused results matching user criteria

✅ Summary

Aspect	Description
Filtering Purpose	Select subset of data matching conditions
SQL Filtering	Use WHERE clause
ADO.NET Filtering	Use DataTable.Select or DataView.RowFilter
LINQ Filtering	Use `where` clause or `.Where()` method
Logical Operators	AND, OR, NOT for complex conditions
Pattern Matching	Use LIKE and IN for flexible filtering

"Databases"

🔷 What is a Database?

🔷 Purpose of a Database

🔷 Types of Databases

🔷 Key Components of a Relational Database

🔷 Common Database Terms

🔷 How .NET Interacts with Databases

🔷 Example Table: Students

🔷 Benefits of Using Databases in Applications

✅ Summary

"Database Transaction"

🔷 What is a Database Transaction?

🔷 Properties of Transactions – ACID

🔷 Example Scenario

🔷 Transaction in SQL (Basic Syntax)

🔷 Using Transactions in ADO.NET (VB.NET Example)

🔷 Benefits of Using Transactions

✅ Summary

"ADO.NET"

🔷 What is ADO.NET?

🔷 Key Features of ADO.NET

🔷 ADO.NET Architecture

🔷 Key ADO.NET Objects

🔷 Example: Simple ADO.NET Flow

🔷 Connected vs Disconnected Model

🔷 Advantages of ADO.NET

✅ Summary

"DataSet in ADO.NET"

🔷 What is a DataSet?

🔷 Key Features of DataSet

🔷 DataSet Structure

🔷 Basic Syntax (VB.NET Example)

🔷 Working with DataSet

🔷 Differences: DataSet vs DataReader

🔷 Advantages of DataSet

✅ Summary

"Connecting to a Database"

🔷 What is a Database Connection?

🔷 Key Object: SqlConnection

🔷 Basic Steps to Connect

🔷 Example: Connecting to SQL Server and Retrieving Data

🔷 Important Properties and Methods

🔷 Best Practices

✅ Summary

“Introduction to Database Programming”

📘 Topic: Introduction to Database Programming

🔷 What is Database Programming?

🔷 Why Database Programming is Important?

🔷 Common Operations in Database Programming

🔷 Tools and Technologies Used

🔷 ADO.NET in Database Programming

🔷 Example: Simple Database Operation (VB.NET)

🔷 Advantages of Database Programming

✅ Summary

“Microsoft Access 2003”

🔷 What is Microsoft Access 2003?

🔷 Features of Microsoft Access 2003

🔷 Objects in Microsoft Access

🔷 Creating a Simple Database in Access 2003

🔷 Common Data Types in Access

🔷 Microsoft Access 2003 with VB.NET / ADO.NET

✅ Example Connection String:

✅ Required Namespace:

🔷 Advantages of Access 2003

🔷 Limitations

✅ Summary

"Database Programming"

🔷 What is Database Programming?

🔷 Why is Database Programming Important?

🔷 Basic Concepts in Database Programming

🔷 Tools Used in Database Programming

🔷 ADO.NET in Database Programming

🔷 Database Programming Workflow in .NET

🔷 Example Code (VB.NET with SQL Server)

🔷 Advantages of Database Programming

✅ Summary

"Bound Controls"

🔷 What are Bound Controls?

🔷 Purpose of Bound Controls

🔷 Examples of Bound Controls

🔷 Example Table: `Students`

🔷 Key Object: `SqlConnection`

✅ `SELECT` – Retrieve data

✅ `INSERT` – Add new record

✅ `UPDATE` – Modify existing data

✅ `DELETE` – Remove data

✅ `CREATE TABLE` – Define a new table

✅ `ALTER TABLE` – Modify table structure

✅ `DROP TABLE` – Delete entire table

✅ `GRANT` – Give permission

✅ `REVOKE` – Take back permission

✅ `COMMIT` – Save transaction permanently

✅ `ROLLBACK` – Undo changes since last commit

✅ `SAVEPOINT` – Set a point to roll back to