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1500 questions
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1 answer

Is it possible to create an alias or synonym for a database?

Is it possible to create a database alias or synonym? What I am hoping to be able to do is have NewDatabaseName aliased as OldDatabaseName to prevent having to rewrite a ton of code. Backstory: I was approached by a client with a ridiculous…
datagod
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1 answer

Term for a one-row table?

Is there a specific term to describe a relation with a cardinality of one? I'm thinking particularly of RDBMS "special" one-row tables, for example, DUAL (Oracle), SYSIBM.SYSDUMMY1 (DB2, Derby) and RDB$DATABASE (Interbase, Firebird).
pilcrow
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2 answers

Difference between row-based and statement-based replication in MySQL?

What is the actual difference between row-based and statement-based replication. I am actually looking in terms of replication's effect on the slave. If I am using row-based replication then what is the effect on the slave and if I am using…
Abdul Manaf
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18
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2 answers

Scaling PostgreSQL TRIGGER(s)

How Postgres triggers mechanism scales ? We have a large PostgreSQL installation and we are trying to implement an event based system using log tables and TRIGGER(s). Basically we would like to create a TRIGGER for each table we want to be…
Ugo Matrangolo
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18
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1 answer

What are the optimal mysqldump settings?

After some search I ended up with the following settings: mysqldump\ --host=localhost\ --port=3306\ --databases ****\ --user=****\ --password=****\ --default-character-set=utf8\ --add-drop-database\ …
user706838
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18
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1 answer

MySQL open_files_limit - cannot change this variable

I'm running into issues because my open_files_limit for mysql is only 1024. Centos 7, MySQL Community Server 5.6.22-log It's actually a vps dedicated to mysql for a WHM server (remote mysql), but that should be beside the point. Config…
user24601
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18
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6 answers

Transaction Log won't shrink, DB thinks it is replicating

I've got a SQL Server 2008 R2 Express database running Kaspersky Security Center, and I have no idea under what circumstances the install happened, but the database appears to think that it's being replicated and will not free any space from the…
Sammitch
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18
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4 answers

SQL Server Max Memory not limiting use of RAM

I would like your input on this. I have a sql server 2008r2 Ent. Ed. 64bit with 16 cores and 64GB RAM. There is one instance of SQL server patched fully as of 20111014. The max ram is set to 60000MB. Amount of free ram is 0 according to task manager…
Martin Sjöberg
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18
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3 answers

EXCEPT operator vs NOT IN

The EXCEPT operator was introduced in SQL Server 2005 but what is the difference between NOT IN and EXCEPT ? Does it do the same? I would like a simple explanation with an example.
Heisenberg
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7 answers

What is a good way to store a large number of columns?

I have a problem deciding how to store this data in my database. Any suggestions on the best way to do it? I don't know a hell of a lot about databases, I might add. I have data coming in formatted like so, but rather than 4, the number of columns…
James
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18
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1 answer

How to index a query with `WHERE field IS NULL`?

I have a table with lots of inserts, setting one of the fields (uploaded_at) to NULL. Then a periodic task selects all the tuples WHERE uploaded_at IS NULL, processes them and updates, setting uploaded_at to current date. How should I index the…
Kirill Zaitsev
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18
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2 answers

What are database statistics, and how can I benefit from them?

I've heard mention of statistics that SQL Server keeps by default. What are they tracking, and how can I use this information to improve my database?
goric
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2 answers

"Copying to tmp table" extremely slow

This is my example of query: SELECT nickname, CASE class_id WHEN 1 THEN 'Druid' WHEN 2 THEN 'Necromancer' WHEN 3 THEN 'Mage' WHEN 4 THEN 'Priest' WHEN 5 THEN 'Warrior' WHEN 6 THEN 'Stalker' WHEN 7…
Gofrolist
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18
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1 answer

PostgreSQL complaining about shared memory, but shared memory seems to be OK

I've been performing kind of intensive schema dropping and creating over a PostgreSQL server, but now complains..: WARNING: out of shared memory ERROR: out of shared memory HINT: You might need to increase max_locks_per_transaction. But the…
48347
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18
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4 answers

Is there any benefit of a primary key that comprises all columns of the table?

I have a table with four columns that are all non-nullable, and the data is such that all four are needed to distinguish a unique record. This means that if I were to make a primary key, it would need to comprise all columns. Queries against the…
goric
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