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Tag: ef-core

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2026-09-27 ef-core ef-core-11 sql-server

How to add a unique index on a JSON-mapped property in EF Core 11 (SQL Server and SQLite)

HasIndex(...).IsUnique() on a ToJson() member does not enforce uniqueness in EF Core 11 RC 1: SQL Server drops IsUnique and SQLite indexes the whole document. Expose the JSON value as a computed column and put the unique index on that instead.

2026-09-21 ef-core ef-core-10 postgresql

How to atomically append to a PostgreSQL jsonb array with EF Core and Npgsql

Loading an entity, calling List.Add, and saving rewrites the whole jsonb document and silently loses concurrent appends. Push the append into one UPDATE with the jsonb || operator, either through ExecuteSqlAsync or a mapped function inside ExecuteUpdateAsync, and make it idempotent with a @> guard.

2026-09-21 ef-core ef-core-10 oracle

How to use an Oracle sequence to generate primary keys in EF Core

Map an EF Core key to an Oracle sequence with UseSequence in Oracle.EntityFrameworkCore 10: the DDL and INSERT SQL the provider really emits, how to point at an existing sequence or a legacy trigger, why quoting and HiLo trip people up, and how to move an identity column onto a sequence without ORA-00001.

2026-09-20 ef-core ef-core-11 scaffolding

How to add custom table-name pluralization to dotnet ef dbcontext scaffold with IPluralizer

A table named Gas scaffolds to an entity called Ga. Replace the built-in Humanizer pluralizer with your own IPluralizer, register it through IDesignTimeServices in the startup project, and learn why TryAddSingleton silently does nothing there.

2026-09-20 ef-core ef-core-11 concurrency

How to guarantee idempotent message processing with EF Core 11 when two app instances consume the same message

The existence check in your handler is not the guard you think it is. Put a unique index on the inbox table, write the marker in the same SaveChanges as the business change, and let the database pick the winner. Plus the ExecuteUpdate trap that quietly undoes all of it.

2026-09-19 ef-core ef-core-11 migrations

How to apply custom naming conventions for primary keys, foreign keys, and indexes in EF Core 11 migrations

Rename every PK_, FK_, AK_ and IX_ that EF Core 11 generates with one IModelFinalizingConvention, keep explicit names winning, stay under the identifier length limit, and avoid the clustered-index rebuild the next migration scaffolds on an existing database.

2026-09-16 comparison ef-core ef-core-11

SQL Server compatibility level 150 vs 160: what changes for EF Core 11 queries

EF Core 11 now defaults UseSqlServer to compatibility level 160, which puts LEAST, GREATEST and two-argument LTRIM/RTRIM into your SQL, including every Take(n).FirstOrDefault(). Keep 160 on SQL Server 2022 and later; pin UseCompatibilityLevel(150) if any environment still runs SQL Server 2019.

2026-09-15 errors ef-core ef-core-11

Fix: EF Core MigrateAsync and CanConnectAsync keep retrying on 'Login failed for user' for 60 seconds

EF Core's SQL Server existence check retries error 18456 for a full minute, with or without EnableRetryOnFailure. Fail fast, cap RetryTimeout, or wait for EF Core 12.

2026-09-14 errors ef-core ef-core-11

Fix: Could not load file or assembly 'Microsoft.Data.SqlClient, Version=7.0.0.0' after updating EF Core

EF Core 11 is compiled against Microsoft.Data.SqlClient 7.0.0.0, but a 6.x copy won the restore or the deploy. Remove the old SqlClient pin and redeploy the full output.

2026-09-12 ef-core ef-core-11 dotnet-11

How to escape % and _ wildcards in EF.Functions.Like and StartsWith queries in EF Core 11

StartsWith, EndsWith and Contains already escape % and _ for you in EF Core 11, but EF.Functions.Like does not. Here is the SQL EF generates, a reusable escape helper, and the escapeCharacter overload that makes it work on SQL Server, SQLite and PostgreSQL.