sql-server

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.

Use the native json type on SQL Server 2025 and Azure SQL: EF Core 11 gets JSON_CONTAINS, typed JSON_VALUE, in-place modify() and JSON indexes out of it. Stay on nvarchar(max) for SQL Server 2019/2022, legacy tooling, or a schema you must be able to roll back.

EF Core emits [col] json '$.path' AS JSON inside OPENJSON WITH, which Azure SQL rejects with Msg 13618. Upgrade to EF Core 10.0.11+, or drop the provider compatibility level to 160.

EF Core 11 still has no lock API. Here is how to take a real row lock with FromSql: WITH (UPDLOCK, ROWLOCK) on SQL Server, FOR UPDATE on PostgreSQL, the subquery trap that silently widens the lock, NOWAIT and SKIP LOCKED, deadlock retries, and what to do when the row does not exist yet.

EF Core's Migrate() always checks whether the database exists and creates it if not, from a hardcoded master connection. Grant CREATE ANY DATABASE, fix the login's access to the existing database, or ship an idempotent SQL script instead.

Move a key off IDENTITY and onto a SQL Server sequence in EF Core 11 with UseSequence: the exact SQL EF emits, why explicit key values suddenly work without IDENTITY_INSERT, the bigint sequence feeding an int column, and the gaps you have to design around.

Use FromSql on a DbSet when the procedure returns full entity rows, Database.SqlQuery<T> when it returns a projection, and ExecuteSql when it returns nothing. Never chain a LINQ operator onto an EXEC, and never read an output parameter before the reader is disposed.

EF Core scaffolds RenameTable when you change the table name, but DropTable plus CreateTable when you rename the entity class. Here is how to tell the two apart, the ToTable trick that makes a class rename free, and the column-rename bug that silently swaps your data.

Add a rowversion concurrency token in EF Core 11: the [Timestamp] and IsRowVersion setup, the SQL EF actually emits, catching DbUpdateConcurrencyException, store-wins vs client-wins vs merge, disconnected APIs with ETags, and the five traps that silently disable the whole thing.

Map a nested type to a single JSON column with ComplexProperty(...).ToJson(), let EF Core 11 store it in the native SQL Server 2025 json type, then query into it with LINQ that translates to JSON_VALUE, JSON_CONTAINS, and JSON_PATH_EXISTS.