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Aug
1
comment Why does dropping a MVIEW trigger a full refresh?
@Raj: thanks, after doing some more tests, I came up with the came conclusion.
Aug
1
comment Files - in the database or not?
You might be interested in this: research.microsoft.com/apps/pubs/default.aspx?id=64525 a research by Microsoft that shows that storing blobs in the database is actually faster than in the file system (for some sizes of blobs at least). This is in line with my tests that showed that for medium sized blobs (< ~1MB) e.g. Postgres is also faster than a filesystem. For Oracle it's about the same performance but I haven't tested the new securefile storage format yet (but they claim it's faster than the old storage format)
Jul
31
comment How to create an oracle dump(.dmp) file using Toad?
You can use dbms_datapump from any SQL client
Jul
31
comment Connect to Postgresql 9.2 from Eclipse Data Tools Platform
What's unclear about "database "database" does not exist"
Jul
31
comment Why does dropping a MVIEW trigger a full refresh?
@PaulWhite: hmm, I cannot log in on meta (clicking on "Log in" simply does nothing) and when I click on "Ask Question" (without logging in) I get an error message (in the browser) that the website redirects my request so that it can never be finished.
Jul
31
comment Does READ UNCOMMITTED have the same effect as AUTOCOMMIT=1?
Which DBMS are you using? Not all actually support "read uncommitted"
Jul
30
comment Formal name for functions that use the OVER clause
@JackDouglas: "window functions" is what the SQL standard uses.
Jul
30
comment Checking whether two tables have identical content in PostgreSQL
This will not detect the case when EmpDtl2 has less rows than EmpDtl1 and all existing rows do exist in EmpDtl1.
Jul
29
comment Index that is not used, yet influences query
Does the output of the plan change if you enable the verbose mode using: explain (analyze true, verbose true) ...?
Jul
29
comment PL/pgSQL function or rCTE to detect depth of relations between two tables
You might want to take a step back, post the structures of the tables involved and the actual problem that you want to solve. Maybe there is a way to do that efficiently with a single SQL statement
Jul
29
comment PL/pgSQL function or rCTE to detect depth of relations between two tables
You are mixing explicit joins and implicit joins in the recursive part of your CTE: FROM ebenen, buchstelle bst JOIN ... Don't do that. That creates a cartesian product between ebenen and buchstelle. I'm pretty sure that's not what you intended
Jul
29
comment PL/pgSQL function or rCTE to detect depth of relations between two tables
Did you try a recursive CTE?
Jul
27
comment MySQL CHAR(500)?
Again: did you do any testing that confirms your assumption? I would very much doubt that you'd be able to measure a difference.
Jul
27
comment MySQL CHAR(500)?
"and VARCHAR is a less efficient storage mechanism" - how do you know that? Did you do any performance testing?
Jul
27
comment Why would SELECT * be magnitudes faster than SELECT foo?
The first statements most probably uses the primary key index on id to find the first row. The second one needs to sort the complete result on the (un indexed) val column.
Jul
26
comment Auto increment char varying column prefixed with some characters
"can't we just make any varchar as auto-increament" - that is not the correct question. What you are trying to achieve simply doesn't make sense.
Jul
26
comment How to generate the E-R Diagram of Wordpress using mySQL Workbench
Most probably Wordpress isn't using any foreign keys (as so many off-the-shelf products...)
Jul
26
comment Auto increment char varying column prefixed with some characters
Why would you want to do that? If every key value has the prefix PAT there is no sense in storing it. Create a serial column and a view that formats the number as desired. Additionally: the value of a primary key has no meaning whatsoever. You should not care about the values in that column, the only thing you need to care about is that they are unique.
Jul
25
comment Index on 'GROUP BY' with functions
MySQL doesn't support indexes on expressions or functions
Jul
25
comment Why is my composite index not used for this table?
Half a millisecond doesn't seem to be slow though...