a_horse_with_no_name

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I'm looking for job as a software developer (Java) with focus on relational database technologies (Oracle, PostgreSQL)

	8,125 reputation	bio	website		visits	member for	2 years
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Apr 22	comment	Storing data in PostgreSQL: One table or two? I think a "real" join with the approriate conditions could be more efficient - but it's really hard to tell.
Apr 22	comment	Storing data in PostgreSQL: One table or two? I would start with indexing the foreign key column in the price table as well as the date (from/to) column. Maybe even a combined index on all three (four?) columns to open the planner the ability to use an index only scan. To be honest: 10k rows is absolutely nothing. Go for the best conceptual design at the beginning, tune later if necessary.
Apr 22	comment	Storing data in PostgreSQL: One table or two? A table join is not costly (if correctly indexed). Don't go that road with a single table, the approach with two tables will give you lot less trouble in the long run. And you might even take advantage of Postgres' range types if a price is not defined by a single date but using a from/to combination.
Apr 20	comment	Using MongoDB and PostgreSQL together I'd go for a column with a `JSON` datatype. Don't be afraid of using new features in Postgres - the Postgres team doesn't release features which aren't stable. And 9.2 isn't that new actually). Plus you can make use of the new JSON features in 9.3 once it's there. If you are always fully processing the documents in your application code (rather then using SQL), you could also store JSON in a regular `text` column.
Apr 20	comment	Creating sequence for longer numeric values @JackDouglas: would make sense as well, yes. `99999999999999999999` "complies" with the actual business requirement, that's why I used that.
Apr 19	comment	Tool to export data with all relational data? Jailer claims to be able to do that: sourceforge.net/projects/jailer (I haven't used though)
Apr 18	comment	How to count selectivity rows in PostgreSQL 8.2 8.2 is really old and no longer supported. You should really plan an upgrade to a current version as soon as possible (read: now)
Apr 16	comment	In Postgresql, is it possible to change the maximum number of columns a table can have? What kind of "problem definition" is that? Do you have a CSV file with that many columns? What is the real business problem behind that foolish "problem definition". You could get away with having a column using an array and the array contains the desired number of elements. Or use the `hstore` datatype, each of those columns mapping to a key in the hstore column. Or use a column with JSON datatype, or use a column with an XML data type.
Apr 16	comment	postgres deadlock without explicit locking @Zapadlo: yes, absolutely. Every DBMS will wind up in a deadlock situation with this example.
Apr 16	comment	How do I execute an Oracle SQL script without sqlplus hanging on me? for the first item, simply add an `set define off` at the start of the script. For more details read the manual.
Apr 16	comment	Identical Postgres index scan taking 5x longer on server `actual time` means exactly that: the actual (real) time it took Postgres to process that step.
Apr 16	comment	strategies to get data from diff database Sorry I have no idea what a "diff database" is.
Apr 16	comment	strategies to get data from diff database Why not simply use: `select user_id, rent from rent_table WHERE user_id IN (select user_id from user_table WHERE name='abc')` or a join between the two tables.
Apr 16	comment	How to allow a user to create databases only with a certain prefix? Why not give every user only one database and let them use schemas to separate the name spaces?
Apr 15	comment	Identical Postgres index scan taking 5x longer on server Can you post the explain analyze from the local machine? Did you check if the `postgresql.conf` differs between the two installations? If yes, which config settings are different?
Apr 15	comment	Temporarly disable cache in oracle 11g Which cache? Oracle's buffer cache? The file system cache? The cache inside your harddisk? The cache built into your harddisk controller? There is so many caching going on in a modern computer, you won't be able to disable all of it. I would compare/monitor the logical I/O a statement does. This can be obtained e.g. using SQL*Plus' "autotrace" facility
Apr 15	comment	Oracle Database: View schema without access to data @YasirArsanukaev: yes, correct. I actually only meant `CREATE SESSION` (bad habits...)
Apr 15	comment	Oracle Database: View schema without access to data Creating a user with only the `SELECT_CATALOG_ROLE` (and the `CONNECT` privilege) should do the job.
Apr 12	comment	Recursive query in mysql Why would MVCC get in the way of a recursive query? There are only selects in the procedure which should never be blocked by any other transaction.
Apr 12	comment	mysql column naming conventions for foreign keys @S.Visser: `user` is a reserved word and should not be used as column (or table) name.