Custom Renaming Rules

This sample demonstrates using efcpt.renaming.json to transform legacy database naming conventions (table prefixes, Hungarian notation, column prefixes) into clean, modern C# naming conventions.

The Problem

Many legacy databases use naming conventions that don't translate well to C#:

Database Name	Issue
tblCustomers	"tbl" prefix
cust_first_name	Column prefix + underscores
ord_cust_id	Abbreviated prefixes
item_qty	Abbreviated names

The Solution

The efcpt.renaming.json file maps these legacy names to clean C# names:

Database	C# Entity	C# Property
tblCustomers	Customer	-
cust_first_name	-	FirstName
tblOrders	Order	-
ord_cust_id	-	CustomerId
item_qty	-	Quantity

File Structure

custom-renaming/
├── DatabaseProject/                 # SQL Project with legacy-named tables
│   └── dbo/Tables/
│       ├── tblCustomers.sql
│       ├── tblOrders.sql
│       └── tblOrderItems.sql
├── EntityFrameworkCoreProject/
│   ├── EntityFrameworkCoreProject.csproj
│   ├── efcpt-config.json
│   └── efcpt.renaming.json         # Renaming rules
└── CustomRenaming.sln

efcpt.renaming.json Format

[
  {
    "SchemaName": "dbo",
    "UseSchemaName": false,
    "Tables": [
      {
        "Name": "tblCustomers",
        "NewName": "Customer",
        "Columns": [
          { "Name": "cust_id", "NewName": "Id" },
          { "Name": "cust_first_name", "NewName": "FirstName" }
        ]
      }
    ]
  }
]

Schema Entry Properties

Property	Description
SchemaName	Database schema (e.g., "dbo")
UseSchemaName	Include schema name in generated namespaces
Tables	Array of table renaming rules

Table Entry Properties

Property	Description
Name	Original table name in database
NewName	New name for the generated entity class
Columns	Array of column renaming rules

Column Entry Properties

Property	Description
Name	Original column name in database
NewName	New name for the generated property

Build

dotnet build

Generated Output

After building, the generated entities use the clean names:

// Generated from tblCustomers with renamed columns
public partial class Customer
{
    public int Id { get; set; }           // was: cust_id
    public string FirstName { get; set; } // was: cust_first_name
    public string LastName { get; set; }  // was: cust_last_name
    public string Email { get; set; }     // was: cust_email
    public string? Phone { get; set; }    // was: cust_phone
    public DateTime CreatedDate { get; set; } // was: cust_created_date
    public bool IsActive { get; set; }    // was: cust_is_active

    public virtual ICollection<Order> Orders { get; set; }
}

Tips

1. Start incrementally - Add renaming rules for a few tables first, then expand
2. Use consistent patterns - If all columns have cust_ prefix, document that pattern
3. Keep the renaming file in source control - It's part of your schema mapping
4. Combine with inflector - Enable use-inflector in efcpt-config.json for automatic pluralization

Common Patterns

Remove table prefixes

{ "Name": "tblUsers", "NewName": "User" }
{ "Name": "tbl_Products", "NewName": "Product" }

Remove column prefixes

{ "Name": "usr_id", "NewName": "Id" }
{ "Name": "usr_email", "NewName": "Email" }

Expand abbreviations

{ "Name": "qty", "NewName": "Quantity" }
{ "Name": "amt", "NewName": "Amount" }
{ "Name": "desc", "NewName": "Description" }

Convert snake_case to PascalCase

{ "Name": "first_name", "NewName": "FirstName" }
{ "Name": "created_at", "NewName": "CreatedAt" }