QueryBuilder Tool for .NET

Overview

QueryBuilder is a lightweight utility for dynamically composing LINQ queries in Entity Framework Core. It simplifies filtering, sorting, and pagination logic.

Example [Initial Release]

var query = new QueryBuilder(db.Users) .Where("Age", ">", 18) .OrderBy("LastName") .Skip(10) .Take(20) .Build() .ToList(); //Returns users over 18, sorted by last name, paginated

Example [Latest]

var filter = queryBuilder
.AddJoin(typeof(SalesOrder.SalesOrderDetail), "ProductID", "ProductID", "Inner") .AddJoin(typeof(SalesOrder.SalesOrderHeader), "SalesOrderID", "SalesOrderID", "Inner") .AndWhere("Name", "StartsWith", "Road") .AndWhere("UnitPrice", ">", 2000M, typeof(SalesOrder.SalesOrderDetail)) .OrElse("OrderQty", ">", 20 , typeof(SalesOrder.SalesOrderDetail)) .AndWhere("SalesOrderDetailID", "IN", (115,156), typeof(SalesOrder.SalesOrderDetail)) .Build(_context.Products, _context).Cast() ;

Query Output

` SELECT [p].[ProductID], [p].[ListPrice], [p].[Name], [s0].[SalesOrderDetailID], [s0].[OrderQty], [s0].[ProductID], 
 [s0].[SalesOrderID], [s0].[UnitPrice], [s1].[SalesOrderID], [s1].[OrderDate]
  FROM [Production].[Product] AS [p]
  INNER JOIN (
      SELECT [s].[SalesOrderDetailID], [s].[OrderQty], [s].[ProductID], [s].[SalesOrderID], [s].[UnitPrice]
      FROM [Sales].[SalesOrderDetail] AS [s]
      WHERE ([s].[UnitPrice] > 2000.0 OR [s].[OrderQty] > 20) AND [s].[SalesOrderDetailID] IN (115, 156)
  ) AS [s0] ON [p].[ProductID] = [s0].[ProductID]
  INNER JOIN [Sales].[SalesOrderHeader] AS [s1] ON [s0].[SalesOrderID] = [s1].[SalesOrderID]
  WHERE [p].[Name] LIKE N'Road%'`

Motivation

Modern APIs often require dynamic filtering, sorting, and pagination. QueryBuilder standardizes this logic, reducing boilerplate and improving consistency across endpoints.

Goals

• Provide a fluent API for dynamic query composition
• Support Where,OR,Skip, and Take out of the box
• Support joins Inner,Left,Right,Full Outer
• Support Groupby, Aggregation, Order By
• Allow JSON-based query definitions for frontend integration(API Integration)
• Validation Layer
• Export query into a portable format(JSON/XML) for logging and Debugging
• SQL Injection safety, Query caching and Async support
• Keep the tool lightweight , dependency-free , and EF-Core friendly

New Features

Reusable Dynamic Joins

-Supports multiple entity joins(Inner) with type safe LINQ expressions.
-Process the query in the Database instead of In-Memory
-Supports filter with "==",">=","<=",">","<","!=", "IN","NOT IN", "LIKE" 

Expression Tree Validation

-Clear error handling for type mismatches in Property/parameter expressions.

Front End compatibility

-QueryBuilder is designed to work with frontend framewroks and traditional MVC view through a .NET API.
-Works with AngularJS, ReactJS, MVC Views, jQuery, or any client that can send JSON payloads.
-All query construction is handled server-side.
-clients never need to know EF Core navigation paths or database column names.
-Example Payload:
    -User can specify the root entity dynamically in the JSON request.QueryBuilder will resolve the correct DbSet<T> internally.
    -Filters on related entities automatically create the required joins.
    -Clients do not need to specify JOIN conditions explicitly (Automated JOIN resolution).
    -Pagination support
    
    `{ "RootEntity": "Product",
        "Filters":
                    [ { "Field": "ProductName", "Condition": "==", "Value": "Road-150 Red, 56" },
                      { "Field": "OrderQuantity", "Condition": ">", "Value": 20 } ], 
        "Skip": 0, 
        "Take": 50 }`

Benefits

- No client-side DB knowledge required
- Dynamic queries without writing raw SQL
- Safe and type-checked

Non-Goals [Initial Release Limitations]

• No support for complex joins or groupings , frontend integration , orderBy dynamic properties , advanced filters with nested properties in the initial release

Contribution Guidelines

This is a small , evolving project. If you'd like to contribute:

• Feel free to fork the repo and submit a pull request with clear description
• No formal release or branching rules yet - Please keep the 'master' branch stable
• If you are adding new features, consider updating the README with example
• For questions or ideas , feel free to open an issue.

Coding Standards

• Use .NET 8.0/C# 12