dotnet/efcore · error · InvalidOperationException

Table name must be specified to configure a table-specific p

Error message

Table name must be specified to configure a table-specific property mapping.

What it means

Thrown by TableBuilder.GetStoreObjectIdentifier() at TableBuilder.cs:164 when the StoreObject property is null. This occurs when table-specific property mapping configuration is attempted on a TableBuilder instance that was not created with a specific table name. The TableBuilder requires a StoreObjectIdentifier to know which table the column override applies to.

Source

Thrown at src/EFCore.Relational/Metadata/Builders/TableBuilder.cs:164

    /// <summary>
    ///     Maps the property to a column on the current table and returns an object that can be used
    ///     to provide table-specific configuration if the property is mapped to more than one table.
    /// </summary>
    /// <typeparam name="TProperty">The type of the property to be configured.</typeparam>
    /// <param name="propertyName">The name of the property to be configured.</param>
    /// <returns>An object that can be used to configure the property.</returns>
    public virtual ColumnBuilder<TProperty> Property<TProperty>(string propertyName)
        => new(GetStoreObjectIdentifier(), EntityTypeBuilder.Property<TProperty>(propertyName));

    /// <summary>
    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
    ///     any release. You should only use it directly in your code with extreme caution and knowing that
    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    [EntityFrameworkInternal]
    protected virtual StoreObjectIdentifier GetStoreObjectIdentifier()
        => StoreObject ?? throw new InvalidOperationException(RelationalStrings.MappingFragmentMissingName);

    EntityTypeBuilder IInfrastructure<EntityTypeBuilder>.Instance
        => EntityTypeBuilder;

    #region Hidden System.Object members

    /// <summary>
    ///     Returns a string that represents the current object.
    /// </summary>
    /// <returns>A string that represents the current object.</returns>
    [EditorBrowsable(EditorBrowsableState.Never)]
    public override string? ToString()
        => base.ToString();

    /// <summary>
    ///     Determines whether the specified object is equal to the current object.
    /// </summary>
    /// <param name="obj">The object to compare with the current object.</param>

View on GitHub (pinned to dbf9771522)

Solutions

Ensure ToTable("TableName", tb => { ... }) is used so the TableBuilder has a store object context.
Use the entity-level Property configuration directly if per-table column overrides aren't needed.
Verify you are chaining configuration from the ToTable callback parameter, not from a disconnected builder.

Example fix

// before: builder without table context
var tableBuilder = /* obtained without table name */;
tableBuilder.Property<string>("Name").HasColumnName("col_name"); // throws

// after: configure inside the ToTable callback
modelBuilder.Entity<MyEntity>()
    .ToTable("MyTable", tb =>
    {
        tb.Property<string>("Name").HasColumnName("col_name");
    });

Defensive patterns

Strategy: validation

Validate before calling

// Always configure table-specific overrides inside the ToTable callback where StoreObject is set.
modelBuilder.Entity<MyEntity>().ToTable("MyTable", tb =>
{
    tb.Property<string>("Name").HasColumnName("col_name");
});

Prevention

Use the ToTable(name, Action<TableBuilder>) overload so the builder always has a store object.
Avoid constructing TableBuilder instances directly.

When it happens

Trigger: Calling .Property<T>("ColName").HasColumnName(...) on a TableBuilder whose StoreObject is null — happens when the builder was obtained without a table context, e.g., through an internal API path that didn't initialize the store object.

Common situations: Attempting table-specific column overrides before the entity is mapped to a table. Misusing the builder API or constructing a TableBuilder directly without a StoreObject. API misuse during complex mapping scenarios with multiple tables.

Related errors

AI-assisted analysis of dotnet/efcore@dbf9771522 (2026-08-06). Data as JSON: /api/errors/5aac247493b8b0a7. Report an issue: GitHub.