SQLite Database Basics: Features, Use Cases, and Integration with Entity Framework Core with Simple C# Example

SQLite is a popular database software used to store data in tables. It is a self-contained, serverless, zero-configuration, and transactional SQL database engine. It is commonly used as an embedded database for local/client-side storage in applications such as web browsers, mobile devices, and desktop applications. It is implemented in C and is available as a library that can be integrated into your application. You can use it to store and retrieve data in a lightweight, simple, and flexible way. It is easy to set up and use, and it requires minimal maintenance.

What is an SQLite database?

SQLite is a popular database software used to store data in tables. It is a self-contained, serverless, zero-configuration, and transactional SQL database engine. It is commonly used as an embedded database for local/client-side storage in applications such as web browsers, mobile devices, and desktop applications. It is implemented using C language and is available as a library that can be integrated into your application. You can use it to store and retrieve data in a lightweight, simple, and flexible way. It is easy to set up and use, and it requires minimal maintenance.

What is the database features supported by SQLite?

SQLite supports many of the features that you would expect from a modern database engine, including:

1. Data Types: It supports a variety of data types including NULL, INTEGER, REAL, TEXT, and BLOB.
2. Indexes: You can create indexes on one or more columns of a table to speed up SELECT queries.
3. Transactions: The database supports atomic transactions, which means that all database changes within a transaction are either applied together or not applied at all.
4. Concurrency: It uses a file-based locking mechanism, which allows multiple connections to the database, but only one connection can write to the database at a time.
5. Triggers: You can specify a trigger to execute a set of SQL statements when an INSERT, UPDATE, or DELETE operation is performed on a table.
6. Views: You can create a virtual table that is a pre-defined SELECT statement.
7. Foreign Keys: You can define foreign key constraints to enforce relationships between tables.
8. Full-Text Search: It includes a full-text search engine that can be used to search for specific words or phrases in a database.
9. Replication: It supports replication using the same database file on multiple devices.
10. Extensible: You can extend the database with custom functions and aggregates written in C or other programming languages.

What are the limitations of SQLite databases?

SQLite has some limitations compared to other database management systems. Some of the notable limitations are:

1. Concurrent writes: SQLite uses a file-based locking mechanism, which means that only one connection can write to the database at a time. This can lead to slower performance when multiple connections are trying to write to the database simultaneously.
2. Transactions: SQLite uses a rollback journal to implement transactions. This means that all changes within a transaction are stored in the rollback journal until the transaction is committed. This can cause the database file to grow in size, especially if you have long-running transactions with many changes.
3. Lack of some features: It does not support certain features that are available in other database management systems, such as views, stored procedures, and triggers.
4. Single-file storage: It stores all of its data in a single file on a disk. This can make it more challenging to manage the database and perform specific backups and restores.
5. Limited alter table: You cannot rename a column, remove a column, or add a NOT NULL constraint to a column using the ALTER TABLE statement in SQLite.
6. Limited support for data types: The database has a limited set of data types, and it does not support some data types that are available in other database management systems, such as the date and time types.
7. No support for right outer joins: It does not support right outer joins using the standard INNER JOIN and OUTER JOIN syntax.
8. No support for multiple schemas: It does not support multiple schemas within a single database file. All objects must be stored in a single namespace.
9. No support for user-defined functions: It does not support user-defined functions or stored procedures. You can only use built-in functions or create custom functions using a programming language such as C.
10. Limited support for ALTER TABLE: The ALTER TABLE statement in SQLite has limited functionality. You cannot use it to rename a table, add or remove constraints, or change the data type of a column.
11. No support for transactions on multiple databases: SQLite does not support transactions that span multiple databases.
12. No support for subqueries in the FROM clause: SQLite does not support subqueries in the FROM clause, which means that you cannot use a SELECT statement as the source for a SELECT statement.
13. No support for cross-database foreign keys: It does not support foreign keys that reference tables in other databases.
14. Limited support for outer joins: It does not support full outer joins or right outer joins using the standard INNER JOIN and OUTER JOIN syntax. However, you can use the UNION ALL operator to simulate a full outer join.

A few potential use cases of SQLite

Here are a few of the potential use cases for SQLite:

1. Embedded applications: It is often used as an embedded database in applications such as mobile apps, web browsers, and desktop applications. It is well-suited for this use case because it is self-contained and does not require a separate server process.
2. Prototyping: It is often used for prototyping or developing POCs because it is simple to set up and use. It allows developers to quickly prototype and test ideas without the need to set up a full-fledged database server.
3. Testing: SQLite is commonly used for testing because it is easy to set up and use. It allows developers to create and manipulate test databases without the need for a separate server process.
4. Lightweight data storage: SQLite is a good choice for storing small to medium-sized datasets because it is lightweight and requires minimal resources.
5. Standalone applications: SQLite is often used in standalone applications that do not require a connection to a central database server. It is a good choice for applications that need to store data locally on the device.
6. Internet of Things (IoT) devices: SQLite is often used to store data on IoT devices because it is lightweight and requires minimal resources. It is a good choice for storing small amounts of data on devices with limited memory and storage.

When should we consider using the SQLite database?

We should consider using SQLite if you need a lightweight, self-contained database engine that is easy to set up and use. Some other reasons to consider using SQLite are:

1. Embedded use: It is a good choice for an embedded database because it is a self-contained library that does not require a separate server process. This makes it easy to include in an application and distribute as a single package.
2. Simplicity: It is simple to set up and use. It does not require any configuration, and you can start using it with just a few lines of code.
3. Zero maintenance: It does not require any maintenance or administration, such as backing up the database or tuning performance.
4. Portability: It stores all of its data in a single file on a disk, which makes it easy to copy or move to another machine.
5. Serverless: It does not require a separate server process, which means that you can use it on a machine that does not have a database server installed.
6. Small footprint: It has a small footprint and requires minimal resources, which makes it suitable for use on devices with limited memory and storage.
7. Cross-platform: It is available on a wide range of platforms, including Windows, macOS, Linux, Android, and iOS.

Overall, SQLite is a good choice for applications that need a simple, lightweight, and portable database engine. It is not suitable for large-scale, high-concurrency applications, or applications that require advanced database features such as stored procedures or triggers.

C# Example: How to use EntityFrameworkCore to connect to SQLite

Here is an example of how you can connect to an SQLite database, create an “Employees” table, and perform INSERT and DELETE queries using Entity Framework Core in C#:

First, you will need to install Microsoft.EntityFrameworkCore.Sqlite NuGet package.

Then, you can use the following code to connect to the database and create the “Employees” table:

using Microsoft.EntityFrameworkCore;

namespace ConsoleApp
{
    public class Employee
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public int Age { get; set; }
    }

    public class MyDbContext : DbContext
    {
        public DbSet<Employee> Employees { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlite("Filename=./mydb.db");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            using (var db = new MyDbContext())
            {
                db.Database.EnsureCreated();
            }
        }
    }
}

Below is a simple program to add and delete records to the employee table in the database. Similarly, you can make changes to the Employee objects and call the SaveChanges(), and the same will be reflected in the database table.

using Microsoft.EntityFrameworkCore;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            // Insert a new employee
            using (var db = new MyDbContext())
            {
                var employee = new Employee { Name = "John Smith", Age = 30 };
                db.Employees.Add(employee);
                db.SaveChanges();
            }

            // Delete an employee
            using (var db = new MyDbContext())
            {
                var employee = db.Employees.FirstOrDefault(e => e.Name == "John Smith");
                if (employee != null)
                {
                    db.Employees.Remove(employee);
                    db.SaveChanges();
                }
            }
        }
    }
}

This example uses Entity Framework Core’s database-first approach to create the “Employees” table and perform queries. Entity Framework Core will create the database and tables automatically based on your model classes. The records can be validated in the database using any one of the tools mentioned above.

Note: We will need to adjust the connection string in the OnConfiguring method to specify the correct path to your database file.

What are the tools available for SQLite?

There are several tools available for working with SQLite databases, including:

1. SQLite Browser: SQLite Browser is an open-source, cross-platform tool for creating, designing, and editing SQLite databases. It provides a graphical user interface (GUI) for working with databases and supports importing and exporting data, running SQL queries, and viewing database structure and data.
2. SQLite Manager: SQLite Manager is a Firefox extension that allows you to manage databases. It provides a GUI for working with SQLite databases, and it supports running SQL queries, importing and exporting data, and viewing database structure and data.
3. DB Browser for SQLite: DB Browser for SQLite is an open-source, cross-platform tool for creating, designing, and editing SQLite databases. It provides a GUI for working with SQLite databases and supports importing and exporting data, running SQL queries, and viewing database structure and data.
4. SQLite Expert: SQLite Expert is a commercial tool for working with SQLite databases. It provides a GUI for managing SQLite databases and supports importing and exporting data, running SQL queries, and viewing database structure and data.
5. SQLiteStudio: SQLiteStudio is an open-source, cross-platform tool for working with SQLite databases. It provides a GUI for managing SQLite databases and supports importing and exporting data, running SQL queries, and viewing database structure and data.
6. SQLite Command Line Shell: The SQLite command-line shell is a command-line interface for working with SQLite databases. It allows you to enter SQL commands and view the results, and it is useful for running SQL scripts or performing specific tasks.

These are just a few examples of the tools available for working with SQLite databases. There are many other tools available, and you can choose the one that best fits your needs and preferences.

Conclusion

In conclusion, SQLite is a lightweight and easy-to-use database engine that is well-suited for small to medium-sized applications. It is a self-contained, serverless, zero-configuration, and transactional SQL database engine that is commonly used as an embedded database for local/client-side storage in applications such as web browsers, mobile devices, and desktop applications.

It supports a variety of data types, indexes, transactions, concurrency, and other features, but it has some limitations compared to other database management systems. You should consider using SQLite if you need a simple, lightweight, and portable database engine. Still, it may not be suitable for large-scale, high-concurrency applications, or applications that require advanced database features.

I hope you find the post helpful. Cheers!!!

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