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1500 questions
145
votes
12 answers
How do I move SQL Server database files?
I have a database and want to move the .mdf and .ldf files to another location. But I do not want to stop the MSSQLSERVER service, and I do not want to export to another server.
How can I do this?
user2645263
143
votes
6 answers
Guid vs INT - Which is better as a primary key?
I've being reading around reasons to use or not Guid and int.
int is smaller, faster, easy to remember, keeps a chronological sequence. And as for Guid, the only advantage I found is that it is unique. In which case a Guid would be better than and…
BrunoLM
- 3,043
- 7
- 25
- 22
142
votes
5 answers
Possible to make MySQL use more than one core?
I've been presented with some dedicated MySQL servers that never use more than a single core. I'm more developer than DBA for MySQL so need some help
Setup
The servers are quite hefty with an OLAP/DataWarehouse (DW) type load:
Primary: 96GB RAM, 8…
gbn
- 68,677
- 8
- 158
- 235
142
votes
4 answers
'Access denied; you need (at least one of) the PROCESS privilege(s) for this operation' when trying to dump tablespaces
I am trying to backup mysql using the command
mysqldump -u root -p database_name > backup.sql
, but it is throwing an error:
'Access denied; you need (at least one of) the PROCESS privilege(s)
for this operation' when trying to dump…
subhanshu kumar
141
votes
5 answers
Good explanation of cascade (ON DELETE/UPDATE) behavior
I don't design schemas everyday, but when I do, I try to setup cascade updates/deletes correctly to make administration easier. I understand how cascades work, but I can never remember which table is which.
For example, if I have two tables -…
Johntron
- 1,515
- 2
- 10
- 7
140
votes
3 answers
Advantages and Disadvantages to using ENUM vs Integer types?
Lets say in some random table, you have a column named status. It's real-world values would be either enabled or disabled.
Is it better for this column's data type to be an int/bool (1 or zero) or to use ENUM with the values being enabled and…
Jake Wilson
- 2,277
- 8
- 20
- 23
139
votes
3 answers
PostgreSQL multi-column unique constraint and NULL values
I have a table like the following:
create table my_table (
id int8 not null,
id_A int8 not null,
id_B int8 not null,
id_C int8 null,
constraint pk_my_table primary key (id),
constraint u_constrainte unique (id_A, id_B,…
Manuel Leduc
- 1,501
- 2
- 10
- 5
138
votes
8 answers
Why shouldn't we allow NULLs?
I remember reading this one article about database design and I also remember it said you should have field properties of NOT NULL. I don't remember why this was the case though.
All I can seem to think of is that, as an application developer, you…
Thomas Stringer
- 41,128
- 9
- 109
- 152
136
votes
4 answers
Optimizing queries on a range of timestamps (two columns)
I use PostgreSQL 9.1 on Ubuntu 12.04.
I need to select records inside a range of time: my table time_limits has two timestamp fields and one integer property. There are additional columns in my actual table that are not involved with this…
Stephane Rolland
- 7,003
- 8
- 27
- 39
130
votes
4 answers
Is it safe to delete mysql-bin files?
I have MM Replication in mysql, and I want to squeeze some free space in the box be deleting unnecessary files, I came across these mysql-bin files inside /var/db/mysql/ There are hundreds of those files like mysql-bin.000123, mysql-bin.000223 etc.…
user18530
127
votes
8 answers
How to properly format sqlite shell output?
If I go to mysql shell and type SELECT * FROM users I get -
+--------+----------------+---------------------------------+----------+-----------+--------------------+--------------------+
| USERID | NAME | EMAILID |…
Kshitiz Sharma
- 2,897
- 8
- 27
- 33
126
votes
2 answers
How do I get the current unix timestamp from PostgreSQL?
Unix timestamp is the number of seconds since midnight UTC January 1, 1970.
How do I get the correct unix timestamp from PostgreSQL?
When comparing to currenttimestamp.com and timestamp.1e5b.de I don't get the expected time from PostgreSQL:
This…
Jonas
- 29,165
- 26
- 57
- 64
126
votes
8 answers
Pattern matching with LIKE, SIMILAR TO or regular expressions in PostgreSQL
I had to write a simple query where I go looking for people's name that start with a B or a D :
SELECT s.name
FROM spelers s
WHERE s.name LIKE 'B%' OR s.name LIKE 'D%'
ORDER BY 1
I was wondering if there is a way to rewrite this to become more…
Lucas Kauffman
- 1,593
- 3
- 14
- 18
124
votes
15 answers
PostgreSQL not running on Mac
The error in its entirety reads:
psql: could not connect to server: No such file or directory. Is the
server running locally and accepting connections on Unix domain socket
"/tmp/.s.PGSQL.5432"?
This is my second time setting up Postgresql via…
Michael P.
- 1,901
- 2
- 11
- 8
122
votes
5 answers
Measure the size of a PostgreSQL table row
I have a PostgreSQL table. select * is very slow whereas select id is nice and quick. I think it may be that the size of the row is very large and it's taking a while to transport, or it may be some other factor.
I need all of the fields (or nearly…
Joe
- 1,395
- 2
- 9
- 9