I got an SystemError : error return without exception set error when trying to write a unicode into a blob field into a table inside a FGDB using arcpy.da.UpdateCursor with ArcGIS v10.3 for instance: import arcpy value = u "a unicode string! with some accent éàèû" with arcpy . da . UpdateCursor ( r "c:\\my_fgdb.fgdb\my_table" , [ "blob_field" ] , where_clause = "FID = '0' ) as cursor : for row in cursor : row [ 0 ] = value cursor . updateRow ( row ) I know blob can store string, but is it normal it cannot store unicode?

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FGDB - Error when writing unicode into blob field

MaximeDemers

I got an SystemError : error return without exception set error when trying to write a unicode into a blob field into a table inside a FGDB using arcpy.da.UpdateCursor with ArcGIS v10.3

for instance:

<SPAN class="keyword token">import</SPAN> arcpy

value <SPAN class="operator token">=</SPAN> u<SPAN class="string token">"a unicode string! with some accent éàèû"</SPAN>
<SPAN class="keyword token">with</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>da<SPAN class="punctuation token">.</SPAN>UpdateCursor<SPAN class="punctuation token">(</SPAN>r<SPAN class="string token">"c:\\my_fgdb.fgdb\my_table"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="string token">"blob_field"</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN> where_clause<SPAN class="operator token">=</SPAN>"FID <SPAN class="operator token">=</SPAN> <SPAN class="string token">'0'</SPAN><SPAN class="punctuation token">)</SPAN> <SPAN class="keyword token">as</SPAN> cursor<SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> row <SPAN class="keyword token">in</SPAN> cursor<SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; row<SPAN class="punctuation token">[</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> value
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; cursor<SPAN class="punctuation token">.</SPAN>updateRow<SPAN class="punctuation token">(</SPAN>row<SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

I know blob can store string, but is it normal it cannot store unicode?

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Accepted answers

bixb0012

Since ArcGIS Desktop/ArcMap uses Python 2.x, inserting or updating a Blob field with a Python str object works because str is a sequence of bytes. A Unicode string is a sequence of Unicode code points, not bytes. Since a Blob field is designed to store binary data, you can't directly insert or update a Blob field with a Python Unicode string. If you want to work with Unicode strings in Blob fields, you will need to encode and decode the strings first.

<SPAN class="keyword token">import</SPAN> arcpy

value <SPAN class="operator token">=</SPAN> u<SPAN class="string token">"a unicode string! with some accent éàèû"</SPAN>
<SPAN class="keyword token">with</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>da<SPAN class="punctuation token">.</SPAN>UpdateCursor<SPAN class="punctuation token">(</SPAN>r<SPAN class="string token">"c:\\my_fgdb.fgdb\my_table"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="string token">"blob_field"</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN> where_clause<SPAN class="operator token">=</SPAN>"FID <SPAN class="operator token">=</SPAN> <SPAN class="string token">'0'</SPAN><SPAN class="punctuation token">)</SPAN> <SPAN class="keyword token">as</SPAN> cursor<SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> row <SPAN class="keyword token">in</SPAN> cursor<SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; row<SPAN class="punctuation token">[</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> value<SPAN class="punctuation token">.</SPAN>encode<SPAN class="punctuation token">(</SPAN><SPAN class="string token">'utf8'</SPAN><SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; cursor<SPAN class="punctuation token">.</SPAN>updateRow<SPAN class="punctuation token">(</SPAN>row<SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

All comments

bixb0012

The ArcGIS Text field is actually Unicode: ArcGIS field data types—ArcGIS Help | ArcGIS Desktop

The characters used for text vary by language. To allow text to more easily convert between languages, ArcGIS uses Unicode to encode characters.

MaximeDemers

Hello Joshua,

Thank you for the information about the blob field!

Do you have an idea why storing unicode in text field works?

bixb0012

<SPAN class="keyword token">import</SPAN> arcpy

value <SPAN class="operator token">=</SPAN> u<SPAN class="string token">"a unicode string! with some accent éàèû"</SPAN>
<SPAN class="keyword token">with</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>da<SPAN class="punctuation token">.</SPAN>UpdateCursor<SPAN class="punctuation token">(</SPAN>r<SPAN class="string token">"c:\\my_fgdb.fgdb\my_table"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="string token">"blob_field"</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN> where_clause<SPAN class="operator token">=</SPAN>"FID <SPAN class="operator token">=</SPAN> <SPAN class="string token">'0'</SPAN><SPAN class="punctuation token">)</SPAN> <SPAN class="keyword token">as</SPAN> cursor<SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> row <SPAN class="keyword token">in</SPAN> cursor<SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; row<SPAN class="punctuation token">[</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> value<SPAN class="punctuation token">.</SPAN>encode<SPAN class="punctuation token">(</SPAN><SPAN class="string token">'utf8'</SPAN><SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; cursor<SPAN class="punctuation token">.</SPAN>updateRow<SPAN class="punctuation token">(</SPAN>row<SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

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