In MariaDB check constraint names are not necessarily unique within a schema.
Let's extend the standard table with a column TABLE_NAME.

Alternative approach — add the column CHECK_CLAUSE to the existing INFORMATION_SCHEMA.TABLE_CONSTRAINTS table.

But it's somewhat against the standard logic, where TABLE_CONSTRAINTS only list names, while full constraint metadata is in CHECK_CONSTRAINTS for check, in CONSTRAINT_COLUMN_USAGE for unique and primary keys, and in REFERENTIAL_CONSTRAINTS for foreign keys.

Hi serg I would like to work on this issue. Is it ok with you if I try to investigate it ?

of course! please, go ahead

Thanks for adding this feature this helps with DB migration.
Wondering why CHECK_CLAUSE is only varchar(64) the texts for more or less complex constraints will be truncated .

vlads The field length is probably an oversight, which we will fix in a subsequent push. Thanks for letting us know.

The order of table fields should go:
CONSTRAINT_CATALOG ; CONSTRAINT_SCHEMA ; TABLE_NAME ; CONSTRAINT_NAME ; CHECK_CLAUSE
Will be added in `10.2`.
Regarding the 64 limitation,I found that `nchar` is fixed with `field_length / field_charset->mbmaxlen` used to create well formed string.
What could be done is to detect that we are using "CHECK_CLAUSE" field and to change the logic, instead of `field_charset->mbmaxlen` to send `length`?!

int Field_varstring::store(const char *from,uint length,CHARSET_INFO *cs)

{

  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;

  uint copy_length;

  String_copier copier;

  copy_length= copier.well_formed_copy(field_charset,

                                       (char*) ptr + length_bytes,

                                       field_length,

                                       cs, from, length,

                                       field_length / field_charset->mbmaxlen);

anel Please try to avoid putting workarounds like this:

detect that we are using "CHECK_CLAUSE" field and to change the logic, instead of `field_charset->mbmaxlen` to send `length`

into Field_varstring::store(). This will pollute the code.

Instead, you need to create a Field of a proper data type. Maybe TEXT.
Thanks.

Hi bar,
thank you for letting me know how to proceed, I definitely learned something new
Here is a patch to solve this:
https://github.com/MariaDB/server/commit/eff1c437f24fa24d17b58283670a95a5d8807271
This patch is applied as new commit to PR #1127 and PR #1150 which are waiting to be merged.
Thanks.