maria-developers team mailing list archive

[Vicențiu Ciorbaru <vicentiu@xxxxxxxxxxx>]

Hi Anel!

I've reviewed your patch and generally things look good. You do some good
analysis usually and I think we should highlight your work to the broader
developer scene. I've thus CC'ed this email to the maria-developers mailing
list. This gives us a chance to get feedback from outside, particularly as
this feature is of general interest to the community.

Please include the .result files in future versions as it makes reviewing a
lot easier.

Serg: coding style and implementation aside, I'll do the review on that
bit, please have a look at Anel's patch and suggest if you think the
current table header for I_S.check_constraints is good enough for our needs
or if you have more input on this task.

Relevant bit:

+ST_FIELD_INFO check_constraints_fields_info[]=
+{
+  {"CONSTRAINT_CATALOG", FN_REFLEN, MYSQL_TYPE_STRING, 0, 0, 0,
OPEN_FULL_TABLE},
+  {"CONSTRAINT_SCHEMA", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0, 0, 0,
+   OPEN_FULL_TABLE},
+  {"CONSTRAINT_NAME", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0, 0, 0,
+   OPEN_FULL_TABLE},
+  {"TABLE_SCHEMA", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0, 0, 0,
OPEN_FULL_TABLE},
+  {"TABLE_NAME", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0, 0, 0,
OPEN_FULL_TABLE},
+  {"CHECK_CLAUSE", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0, 0, 0,
+   OPEN_FULL_TABLE},
+  {0, 0, MYSQL_TYPE_STRING, 0, 0, 0, SKIP_OPEN_TABLE}
+};

Vicențiu

On Thu, 29 Mar 2018 at 12:01 Anel Husakovic <anel@xxxxxxxxxxx> wrote:

> Hi Vin,
>
> I'm pleased to announce my new patch prototype for MDEV 14474 where are
> implemented field and table constraints:
>
> https://github.com/an3l/server/commit/f92fd77d2695be52faf280245faa014c44617aa7
>
> According to the standard there are only 4 column to represent.
> CONSTRAINT_CATALOG, CONSTRAINT_SCHEMA, CONSTRAINT_NAME,CHECK_CLAUSE
> But because Serg mentioned that alternative would be to change
> *information_schema.table_constraints* with adding only 1 column (
> *check_clause*) I also used 2 additional columns which are represented
> also in *table_constraints *and they are TABLE_SHEMA , TABLE_NAME.
>
> Function of interest is: get_check_constraints_record
>
> Also I added 2 test cases:
>
> One that works with only 1 table:  MDEV14474-one_table_play.test
> <https://github.com/an3l/server/commit/f92fd77d2695be52faf280245faa014c44617aa7#diff-2267c689543c97ce71367793d38d4581>
> Second that works with more tables:  MDEV14474-I_S_check_constraint.test
> <https://github.com/an3l/server/commit/f92fd77d2695be52faf280245faa014c44617aa7#diff-55f166b9ea0852676b6810a441f91cf5>
>
> Last night I had a problem with field constraints.
> As a reference I used only way how currently all check constraints are
> shown and its obtained via* show create table t;*
>
> Bellow is shown that  field constraints were not visible as well as that
> name used for them is *NULL*, at least this is how *show create table*
> represented them ( there is no way to give a name to a field constraint*
> for example: f int constraint name check(f<0)*). According to my opinion,
> because this constraint belongs to the field, it should be also called as a
> name of a field and not NULL.
> As an argument to my opinion here is mariadb  kb
> https://mariadb.com/kb/en/library/constraint/
> Please take a look at *constraint **name*, which is field constraint and
> error message.
>
> INSERT INTO t2(name, start_date, end_date) VALUES('Io', '2003-12-15', '2014-11-09');ERROR 4022 (23000): CONSTRAINT `name` failed for `test`.`t2`
>
> If the name of constraint = name of the field , than definitely it is not
> consistent with* show create table* output, and *show create table*
> output *needs to be changed*,  , but this is question that I would like
> to discuss with you ?!
>
> When you try to use show create table x
> [image: image.png]
>
>
> I'm waiting on your reply for global temporary tables as well as
> check_constraints and how to proceed further
>
> *Not understand yet a concept*:
>
> In *sql/table.h*
> There is a struct* st_schema_table *which has fill data and process data.
>
> How they work, and how to use that on other database for example PSI.
>
> Regards,
>
> Anel
>