# Insert NULL into varbinary(max) field throws

**URL:** <https://forum.inductiveautomation.com/t/insert-null-into-varbinary-max-field-throws/114291>\
**Category:** Ignition\
**Created:** [March 3, 2026, 3:00pm UTC](https://forum.inductiveautomation.com/t/insert-null-into-varbinary-max-field-throws/114291 "2026-03-03T15:00:16Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![ShaneH](https://avatars.discourse-cdn.com/v4/letter/s/3e96dc/32.png) [@ShaneH](https://forum.inductiveautomation.com/u/ShaneH)\
**Post date:** [March 3, 2026, 3:00pm UTC](https://forum.inductiveautomation.com/t/insert-null-into-varbinary-max-field-throws/114291/1 "2026-03-03T15:00:16Z")

</div>

Ignition 8.3.3, SQL Server 2025 DB  
Using Microsoft SQLServer driver as shipped with Ignition.

I have a table with two columns:

```python
[name] [varchar](50) NOT NULL,
[data] [varbinary](max) NULL,

```

Attempting to insert a NULL/None into varbinary field:

```python
    query = 'insert into groups (name,data) values (?,?)'
    args = ['foo', None]
    system.db.runPrepUpdate(query, args)

```

Throws with:

> Implicit conversion from data type nvarchar to varbinary(max) is not allowed. Use the CONVERT function to run this query.

Any ideas?

-Shane

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<div class="post-metadata">

**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [March 3, 2026, 3:07pm UTC](https://forum.inductiveautomation.com/t/insert-null-into-varbinary-max-field-throws/114291/2 "2026-03-03T15:07:05Z")

</div>

The error message says you must **explicitly** cast the value. Something like this:

```python
insert into groups (name,data) values (?,cast(? as varbinary))

```

---

<div class="post-metadata">

**Author:** ![ShaneH](https://avatars.discourse-cdn.com/v4/letter/s/3e96dc/32.png) [@ShaneH](https://forum.inductiveautomation.com/u/ShaneH)\
**Post date:** [March 3, 2026, 3:12pm UTC](https://forum.inductiveautomation.com/t/insert-null-into-varbinary-max-field-throws/114291/3 "2026-03-03T15:12:15Z")

</div>

Directly from SSMS or from the Designer’s built-in database query browser:

> insert into groups (name,data) values (‘foo’,NULL)

works without the cast/convert.

I suspect that the parameter binding (?,?) is getting confused and casting the None to a string (or other bytes type) before calling the SQL driver.

-Shane

---

<div class="post-metadata">

**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [March 3, 2026, 3:15pm UTC](https://forum.inductiveautomation.com/t/insert-null-into-varbinary-max-field-throws/114291/4 "2026-03-03T15:15:36Z")

</div>

IIRC, Ignition's guts simply hands the null to the JDBC driver. Null is fundamentally untyped in java, so there's no way to indicate to SQL unless supplied in the query as a constant.

SSMS doesn't use JDBC, so it isn't comparable anyways.

The cast doesn't hurt anything if you pass an actual byte array. Consider it a "type hint" for cases that JDBC cannot figure out on its own.

---

<div class="post-metadata">

**Author:** ![ShaneH](https://avatars.discourse-cdn.com/v4/letter/s/3e96dc/32.png) [@ShaneH](https://forum.inductiveautomation.com/u/ShaneH)\
**Post date:** [March 3, 2026, 3:26pm UTC](https://forum.inductiveautomation.com/t/insert-null-into-varbinary-max-field-throws/114291/5 "2026-03-03T15:26:06Z")

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It may well be an issue with the JDBC driver. However, every other type I’ve tried (int, varchar, etc.) allowed passing and inserting a NULL/None without having to cast/convert in the SQL itself.

I thought it worth reporting in case is was something specific to way Ignition was handling it.

-Shane

---

<div class="post-metadata">

**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [March 3, 2026, 3:28pm UTC](https://forum.inductiveautomation.com/t/insert-null-into-varbinary-max-field-throws/114291/6 "2026-03-03T15:28:57Z")

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No, it occurs for other types, too--I've often had to use it with datetime types, and for other DB flavors. (Only for nullables.) Getting away without it relies on **implicit** conversion, which varies by DB brand.

(I prefer PostgreSQL's double colon cast operator as a more readable alternate, but that is non-standard, unfortunately.)