How create Clob field in Design View in Base - Firebird?

I created an embedded Firebird-database.
I 'll try to create a table (TABLE1) in Design View a field COMMENT with a CLOB-field type. When I click on save, the field type changes from CLOB[BLOB] to BLOB[BLOB]. When I re-open for editing this table TABLE1, I see there on the field type BLOB[BLOB]. The field COMMENT is the last field in the table.
What is now the actual field type of COMMENT?

This behavior is different when the last field is not a CLOB. See TABLE2, there is in Field Type CLOB[BLOB] for COMMENT.
The problem is when you want to add a field, and save the table, you get "The column “COMMENT” could not be changed. ". But I have not touched it? I cannot anymore change that TABLE2


My questions is now:
What are the actual field types of COMMENT in the 2 tables?
How to use Table Designer with CLOB-fields?

LibreOffice Version: (x64) on Windows10 with Firebird embed.


There are still quite a few bugs regarding Firebird and you may want to examine those in Bugzilla.

Have tested your file using Mint 18.3 & LO v6.2.3.2 and your Table2. When adding a new field to the end got the warning message but selected NO & table seems to be OK:

Also had no problems with creating new tables with CLOB or BLOB fields no matter where they were placed. This may be due to the version you have installed.

This is sadly still a problem on Win7 and Win10 /Base 6.4.3 / Firebird & GUI methods on empty tables:

  • CLOB can only be created via the wizard…

  • CLOB will not save in design-table view …

  • And any changes to any other field in a table with CLOB / BLOB will result in all CLOB / BLOB being turned to BLOB…!!!(language - please!)

  • It is not possible to alter a CLOB to another type or vice-versa, and same is true for tables copied in from HSQL2.x project:

"firebird_sdbc error: *unsuccessful metadata update " …sadness:(

quickly tried in Libre7.0dev + Libre6.4 with HSQL+Firebird, and with experimental-features on/off:

Results are the same:
CLOBs can only be created in Wizard/when first creating a table in design-view.
Any additional CLOB added to that table in edit-view once saved for the first time will always revert to BLOB.


Appears this is tdf#121553

All further comments should be noted there.

not quite a proper solution to the exact question, but …

now I have switched to Firebird External on JDBC connector and can use additional DB mangers like FlameRobin, many tasks (including CLOB issues) are now much easier to fix … Firebird Embedded will likely always be a bit sub-optimal for ‘true’ DB design when fully confined within LO