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Groups > comp.lang.java.programmer > #37260
| From | Sebastian <nowhere@nirvana.org> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Which databases are the most used with Java |
| Date | 2017-08-17 23:33 +0200 |
| Organization | albasani.net |
| Message-ID | <on5247$q8$1@news.albasani.net> (permalink) |
| References | (3 earlier) <omptib$5qm$1@news.albasani.net> <evbk6cFud9oU1@mid.individual.net> <878tins1li.fsf@munus.decebal.nl> <omqchj$3n6$1@news.albasani.net> <on2r27$1ujh$1@gioia.aioe.org> |
Am 17.08.2017 um 03:21 schrieb Arne Vajhøj: > On 8/13/2017 4:24 PM, Sebastian wrote: [snip] >> and >> surprising things can happen, starting with your mapping from database >> types to Java SQL types (NUMERIC?, REAL?, DECIMAL?... - and this can >> change even when updating from version of a driver to another of the >> same vendor). > > ???? > > JDBC defines mapping for standard types. > > NUMERIC and DECIMAL maps to BigDecimal. > > REAL maps to float or Float depending on context. [snip] I did not mean that mapping, but the step before it, concerning metadata: the mapping of database types (what you put in the CREATE TABLE statement to define the columns) to standard types, i. e. constants in java.sql.Types. With Oracle, you may get a description of all supported data types with DatabaseMetadata.getTypeInfo(), or call DatabaseMetadata.getColumns() on a table. Case in point: When Oracle updated the JDBC driver from 12.1.0.1 to 12.1.0.2 (in ojdbc7) they did some changes and some bug-fixing, and my metadata-dependent code was bitten by the driver suddenly returning NUMERIC instead of DECIMAL for some NUMBER columns and NVARCHAR instead of OTHER for NVARCHAR2 columns. (The code wasn't any good in the first place, let's not argue about that...) Along came 12.2.0.1 (ojdbc8) , and I was happy it behaved the same way as 12.1.0.2, but still I had had to write all those automatic regression tests. Metadata is one of the areas where there's little standardization, and drivers from different vendors differ to a greater extent. In part this is understandable, because the type inventories differ so much. But even when types are practically identical between vendors, you may get different metadata. For example, in SQL Server DECIMAL and NUMERIC are synonymous in the database, but still they chose to map them to the two respective Types constants (which have no such synonymity assumption) instead of choosing the same target for both. In some other databases, java.sql.Types.NUMERIC is mapped from some integer type. Sorry for the lengthy clarification. I'd like to avoid to get side-tracked in this thread. I just wanted to point out one possible pitfall in designing a vendor-independent layer above JDBC. -- Sebastian
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Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 07:58 +0200
Re: Which databases are the most used with Java Marcel Mueller <news.5.maazl@spamgourmet.org> - 2017-08-13 09:33 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 11:14 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 16:53 -0400
Re: Which databases are the most used with Java Sebastian <nowhere@nirvana.org> - 2017-08-13 09:36 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 11:07 +0200
Re: Which databases are the most used with Java Andreas Leitgeb <avl@logic.at> - 2017-08-13 09:46 +0000
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 12:12 +0200
Re: Which databases are the most used with Java Robert Klemme <shortcutter@googlemail.com> - 2017-08-13 17:47 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 19:11 +0200
Re: Which databases are the most used with Java Robert Klemme <shortcutter@googlemail.com> - 2017-08-13 20:26 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 21:30 +0200
Re: Which databases are the most used with Java Martin Gregorie <martin@address-in-sig.invalid> - 2017-08-13 20:00 +0000
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 16:43 -0400
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 16:42 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 23:18 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 20:41 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-14 03:04 +0200
Re: Which databases are the most used with Java lewbloch@gmail.com - 2017-08-14 11:12 -0700
Re: Which databases are the most used with Java Eric Douglas <e.d.programmer@gmail.com> - 2017-08-14 12:42 -0700
Re: Which databases are the most used with Java Robert Klemme <shortcutter@googlemail.com> - 2017-08-21 22:25 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-21 19:50 -0400
Re: Which databases are the most used with Java Eric Douglas <e.d.programmer@gmail.com> - 2017-08-14 13:48 -0700
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-15 07:27 +0200
Re: Which databases are the most used with Java Martin Gregorie <martin@address-in-sig.invalid> - 2017-08-15 10:25 +0000
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-15 14:15 +0200
Re: Which databases are the most used with Java Martin Gregorie <martin@address-in-sig.invalid> - 2017-08-15 14:37 +0000
Re: Which databases are the most used with Java lewbloch@gmail.com - 2017-08-17 14:52 -0700
Re: Which databases are the most used with Java Sebastian <nowhere@nirvana.org> - 2017-08-18 00:09 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-17 18:14 -0400
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-17 18:19 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-18 06:43 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-15 11:02 -0400
Re: Which databases are the most used with Java Patrick Roemer <sangamon@netcologne.de> - 2017-08-15 13:12 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-15 14:41 +0200
Re: Which databases are the most used with Java Eric Douglas <e.d.programmer@gmail.com> - 2017-08-15 06:11 -0700
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-15 16:33 +0200
Re: Which databases are the most used with Java Eric Douglas <e.d.programmer@gmail.com> - 2017-08-15 08:05 -0700
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-15 18:48 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-15 11:12 -0400
Re: Which databases are the most used with Java Eric Douglas <e.d.programmer@gmail.com> - 2017-08-15 08:19 -0700
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-15 11:46 -0400
Re: Which databases are the most used with Java Eric Douglas <e.d.programmer@gmail.com> - 2017-08-15 08:43 -0700
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-15 11:51 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-15 18:38 +0200
Re: Which databases are the most used with Java Patrick Roemer <sangamon@netcologne.de> - 2017-08-15 16:14 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-15 17:42 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-15 11:09 -0400
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-15 11:06 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-15 18:42 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-16 21:13 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-17 09:04 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-17 18:16 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-18 06:51 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-18 08:52 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-18 15:31 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-18 15:09 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-18 23:14 +0200
Re: Which databases are the most used with Java Eric Douglas <e.d.programmer@gmail.com> - 2017-08-18 07:15 -0700
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-18 15:16 -0400
Re: Which databases are the most used with Java Sebastian <nowhere@nirvana.org> - 2017-08-13 18:08 +0200
Re: Which databases are the most used with Java Robert Klemme <shortcutter@googlemail.com> - 2017-08-13 20:30 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 21:35 +0200
Re: Which databases are the most used with Java Sebastian <nowhere@nirvana.org> - 2017-08-13 22:24 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 23:33 +0200
Re: Which databases are the most used with Java Robert Klemme <shortcutter@googlemail.com> - 2017-08-14 18:18 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-15 07:47 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-16 21:21 -0400
Re: Which databases are the most used with Java Sebastian <nowhere@nirvana.org> - 2017-08-17 23:33 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-17 18:11 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 23:24 +0200
Re: Which databases are the most used with Java Robert Klemme <shortcutter@googlemail.com> - 2017-08-14 18:14 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-15 07:45 +0200
Re: Which databases are the most used with Java Sebastian <nowhere@nirvana.org> - 2017-08-13 22:16 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 16:50 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 23:35 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 21:14 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-14 10:24 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 16:45 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-13 23:36 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 20:42 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-14 03:06 +0200
Re: Which databases are the most used with Java lewbloch@gmail.com - 2017-08-13 09:59 -0700
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 17:04 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-14 00:06 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-14 00:35 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 20:44 -0400
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-14 03:12 +0200
Re: Which databases are the most used with Java Arne Vajhøj <arne@vajhoej.dk> - 2017-08-13 16:59 -0400
Re: Which databases are the most used with Java Joerg Meier <joergmmeier@arcor.de> - 2017-08-16 07:26 +0200
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-16 09:40 +0200
Re: Which databases are the most used with Java Graeme Geldenhuys <graemeg@example.net> - 2017-08-23 00:15 +0100
Re: Which databases are the most used with Java Cecil Westerhof <Cecil@decebal.nl> - 2017-08-23 12:09 +0200
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