Insertion of geometric type column with column[0], column[1] and etc.
От | Marcelo Zabani |
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Тема | Insertion of geometric type column with column[0], column[1] and etc. |
Дата | |
Msg-id | AANLkTi=1q1ye_yHb-1-CbEN34chJyjzvM4G=UiXHDRkC@mail.gmail.com обсуждение исходный текст |
Ответы |
Re: Insertion of geometric type column with column[0], column[1] and etc.
Re: Insertion of geometric type column with column[0], column[1] and etc. |
Список | pgsql-hackers |
I've been using postgresql with geometric types and I've been using NHibernate as an ORM solution.<br />The problem is thatNHibernate can't map geometric data types to any kind of property of a class (not for insertions).<br /> I've (with partialsuccess, as will be explained) mapped the desired column (in my case, a POINT pgsql type) by mapping from column[0]and column[1].<br />I know I can do updates and selects using column[0] and column[1], but I can't do INSERTS (atleast not if the column has a not-null constraint).<br /> The documentation doesn't say that insertions would work (<a href="http://www.postgresql.org/docs/9.0/interactive/functions-geometry.html">http://www.postgresql.org/docs/9.0/interactive/functions-geometry.html</a>), soI'm not filing this as a bug report.<br /><br />However, with the huge popularity of ORM solutions and the complexity ofdb-specific datatypes (geometric types in other dbs probably work differently), we can't really expect ORM software todo all the mapping successfully (although projects such as Hibernate Spatial exist for java solutions, NHibernate Spatialseems to be abandoned, and there are, of course, other ORM solutions for other platforms).<br /><br />While I haveemphasized the POINT data type, it would be desirable that all types in pgsql could be accessed/updated/inserted withthe array-analogy (or other analogy), so that we could easily map ANYTHING with ORM software these days.<br /><br />Also,just to note, if there isn't a not null constraint on the column, inserting with column[0] and column[1] will inserta null value in that column.<br /><br /><b>The SQL to show what I mean:</b><br />postgres=# create table test (coordinatesPOINT NOT NULL);<br /> CREATE TABLE<br />postgres=# insert into test (coordinates[0], coordinates[1]) values(1,2);<br />ERROR: null value in column "coordinates" violates not-null constraint<br /><br /><b>And then:</b><br/>postgres=# alter table test alter column coordinates drop not null;<br /> ALTER TABLE<br />postgres=# insertinto test (coordinates[0], coordinates[1]) values (1,2);<br />INSERT 0 1<br />postgres=# select * from test where coordinatesis null;<br /> coordinates<br />-------------<br /><br />(1 row)<br /><br /><i>* In the results above, the blankline shows the null value (obviously)</i><br />
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