SQL Server Error 7356

Error number

7356

Severity

16 (user-correctable error)

State

Not documented by Microsoft (not reproduced here)

Product

Microsoft SQL Server Database Engine

Versions

All supported SQL Server versions (2016 to 2025), Azure SQL Managed Instance (supported providers only)

Category

Linked Servers

Last reviewed

24 October 2026

What it means

Error 7356 means a linked server provider described a remote column one way when SQL Server compiled the query and another way when it returned the rows, so SQL Server refused to use the data.

To compile a distributed query SQL Server asks the OLE DB provider for the columns of the remote object: type, length, precision, scale and flags such as nullability. It builds the plan on that answer. At run time it compares the rowset the provider actually returns with what it was told, and any difference in one of these properties stops the query with 7356, because a plan built for, say, a non-nullable 4 byte column cannot safely consume something else.

The message tells you exactly what differed: the column and its position, the remote object, the property (an OLE DB name such as DBCOLUMNFLAGS_ISNULLABLE, a column flag, or a length) and the two values. For flags the numbers are bit masks: DBCOLUMNFLAGS_ISNULLABLE is 32 (0x20) when set, so "0 at compile time and 32 at run time" means the provider first said NOT NULL and then delivered a nullable column.

Common causes

• The provider reports column metadata inconsistently, typically for computed or expression columns of a remote view (for example nullability or length of a column built with a function or a UNION).
• The remote object changed between compile and execution (a column altered, a view redefined) and the cached plan was reused without a schema check, for example with the linked server option lazy schema validation on.
• An older or third-party provider (Oracle, ODBC through MSDASQL, other databases) returns different metadata from its schema rowsets than from the result rowset.
• A provider upgrade or a change of provider for the same linked server, so the plan compiled with one description and runs against another.

Diagnose it

Read-only These queries only read metadata and dynamic management views. They do not change data, permissions or configuration, so they are safe to run first.

SELECT name, provider, product, data_source, lazy_schema_validation,
       is_collation_compatible, uses_remote_collation, modify_date
FROM sys.servers
WHERE is_linked = 1;

SELECT TOP (20) cp.usecounts, cp.objtype, OBJECT_NAME(st.objectid, st.dbid) AS object_name,
       LEFT(st.text, 200) AS query_start
FROM sys.dm_exec_cached_plans AS cp
CROSS APPLY sys.dm_exec_sql_text(cp.plan_handle) AS st
WHERE st.text LIKE N'%ORAHR%'
ORDER BY cp.usecounts DESC;

SELECT c.column_id, c.name, TYPE_NAME(c.user_type_id) AS type_name,
       c.max_length, c.precision, c.scale, c.is_nullable, c.is_computed
FROM sys.columns AS c
WHERE c.object_id = OBJECT_ID(N'dbo.vOrders')
ORDER BY c.column_id;

How to fix it

Each fix is labelled with what it changes. Try read-only checks and the least invasive fix first, and test changes outside production.

SELECT employee_id, manager_id
FROM OPENQUERY(ORAHR,
  'SELECT EMPLOYEE_ID, CAST(NVL(MANAGER_ID, 0) AS NUMBER(6)) AS MANAGER_ID
   FROM HR.EMP_DETAILS_VIEW');

SELECT EMPLOYEE_ID, MANAGER_ID
FROM ORAHR..HR.EMP_DETAILS_VIEW
OPTION (RECOMPILE);

EXEC master.dbo.sp_serveroption
     @server = N'ORAHR', @optname = N'lazy schema validation', @optvalue = N'false';

Examples

A remote view column that the provider calls NOT NULL at compile time

Shown as the documented engine message with example values; not reproduced here. With a temporary loopback linked server using the SQL Server provider (MSOLEDBSQL) our tests of changed and stale remote views either recompiled silently or raised error 7359 (schema version changed), never 7356. Microsoft documents no state for 7356, so no header is shown. Linked server, object and column names are examples.

SELECT EMPLOYEE_ID, MANAGER_ID
FROM ORAHR..HR.EMP_DETAILS_VIEW;

The OLE DB provider "OraOLEDB.Oracle" for linked server "ORAHR" supplied inconsistent metadata for a column. The column "MANAGER_ID" (compile-time ordinal 4) of object ""HR"."EMP_DETAILS_VIEW"" was reported to have a "DBCOLUMNFLAGS_ISNULLABLE" of 0 at compile time and 32 at run time.

How to prevent it

Read remote data through pass-through queries (OPENQUERY or EXEC ... AT) that select named columns with explicit types, rather than four-part names over remote views with expression columns. Leave lazy schema validation off unless you have measured a real need for it.

Treat remote schema changes as deployments for the servers that consume them: after altering a remote table or view, recompile the local procedures that read it and test them.

Common questions

Learn more on CodeWithSQL

• SQL views explained
• SQL NULL values explained

Official documentation

• Database engine events and errors (7000 to 7999)
• OPENQUERY (Transact-SQL)
• sp_serveroption (Transact-SQL)
• Linked servers (Database Engine)

Last technically reviewed 24 October 2026; examples and diagnostics run on SQL Server 2025 (17.0.1145.4). Message text checked against the engine's sys.messages catalogue.