MySQL : Open-Source, Relational Database Management System

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8
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2answers
5k views

Percona vs MySQL

What is Percona? How does it differ from MySQL? When should we consider switching (or upgrading) from stock MySQL to Percona? To add some specifics in our situation we almost exclusively use ...
12
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2answers
21k views

How to SELECT from SHOW TABLE STATUS results

I'd like to limit the rows and columns that come back from the SHOW TABLE STATUS command in MySQL 5.1. Is there a way to get this same information through a SELECT statement so I can manipulate ...
2
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1answer
249 views

Check against multiple duplicate records

I have data that i should insert into table. But before inserting i need to check against duplicate records and report list of those records. Table: CREATE TABLE `test` ( `A` varchar(19) NOT NULL, ...
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1answer
4k views

How to use ON DUPLICATE KEY for UPDATE

Consider a table of CREATE TABLE test ( id int(11) unsigned NOT NULL AUTO_INCREMENT, external_id int(11), number smallint(5), value varchar(255), UNIQUE INDEX (external_id, number), PRIMARY KEY(id) ...
3
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1answer
200 views

Is UNIQUE(), INDEX() different from UNIQUE INDEX()?

Is there any different how mysql treats UNIQUE (column1, column2), INDEX (column1) and UNIQUE INDEX (column1, column2) and UNIQUE (column1, column2) In the latter, I think mysql will ...
5
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2answers
227 views

How should an object that can reference an object of multiple types be modeled in a relational schema?

Apologies for the obscure question, it may make more sense with a concrete example: In my application, I may create a portfolio that contains a set of projects. However, I may also add a ...
4
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2answers
2k views

Access denied for user 'myuser'@10.% to database 'mydb' - Mysql Import SQL Script

I have a database that I am trying to recreate at my web host. I used mysqldump to create a sql script. My web hosting company, IPage, has a hosted mysqladmin site where I am supposed to be able to ...
9
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1answer
4k views

What does 'ibfk' stand for in MySQL?

If I create a foreign key constraint for table 'photos' in phpmyadmin, I later see that the constraint is named 'photos_ibfk_1', and the next constraint is called 'photos_ibfk_2', etc. From this I ...
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1answer
2k views

Does the order of keys in compound Primary key make any difference?

Package Package ------- PackageID PackageName CityID PRIMARY KEY (PackageID) UNIQUE KEY (PackageName) FOREIGN KEY (CityID) REFERENCES City (CityID) Package versions: PackageVersion ...
2
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4answers
3k views

Creating Archiving database for old data in MySQL

I Have a Master and Various Slave Servers. There is a huge amount of the data on all the servers and I wish to create an Archiving system for our Data. Scenario is : I want that only Last one year ...
1
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1answer
246 views

mysql event running at wrong time

I created an event to run every 24 hours and be run at 14h. Its selects some data from tabels and writes it as to a file (csv format) The query and writing to file goes ok. The event is triggered. ...
7
votes
2answers
16k views

How to do a case sensitive search in WHERE clause?

I want case sensitive search in SQL query. But by default, MySQL does not consider the case of the strings. Any idea on how to do a case sensitive search in SQL query?
3
votes
2answers
253 views

Create table statement in MYSQL

I am trying to create the following table in MYSQL and is giving errors, CREATE TABLE CUSTOMER ( CUS_ID INT NOT NULL AUTO_INCREMENT, CUS_NAME VARCHAR, CUS_DOB DATE, CUS_ADDR VARCHAR, CUS_EMAIL ...
5
votes
2answers
2k views

How do I get the execution plan for a view?

I have a schema with a number of views. I need to check the execution plans to make sure the appropriate indexes are in place and being used. How do I do this? I'd rather not have to copy and paste ...
0
votes
1answer
9k views

What's a good (free) client for MySQL on Windows? [closed]

I am almost repeating a question done here by another user, but related to MySQL. What do you think is the best free (if any) MySQL client software? Thank you!
1
vote
1answer
1k views

MySQL import csv only gets half the lines

I use the following command to read in a csv: LOAD DATA INFILE '/Users/Tyler/Desktop/players_escaped.txt' INTO TABLE players FIELDS TERMINATED BY ',' ENCLOSED BY '^' LINES TERMINATED BY '\n'; The ...
0
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2answers
709 views

how to design movies with show times database structure

how to design movies with show times database structure I'm building simple local cinemas guide website using Yii PHP framework. I need Correct and improve this database, specially for showtimes ...
5
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3answers
647 views

how do I model this in database?

I am using mysql as my backend database. Here is the use case; A HolidayPackage is configured with some default offerings. These default offerings can be up/downgraded based on the options provided. ...
2
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1answer
2k views

Sort buffers and tables on disk, MySQL/InnoDB

I have the following type of query frequently running: # Time: 120322 13:03:29 # User@Host: root[root] @ localhost [127.0.0.1] # Query_time: 17.039286 Lock_time: 0.000141 Rows_sent: 24 ...
3
votes
2answers
9k views

How to combine UNION and INNER JOIN?

I'm fetching the grandparent of all nodes in a tree as follows: SELECT P.id, P.parent, GP.parent gp_id FROM product_groups P INNER JOIN product_groups GP ON P.parent = GP.id There is ...
2
votes
1answer
263 views

Using Foreign Keys in database

I am doing a small application for Invoice.In that the tables will be like this === invoice === id (pk) customer_id (fk) invoice_title invoice_issue_date due_date description created_by updated_by ...
2
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1answer
2k views

How to export mysql database based on a where condition

I need to export the data and structure of a table but the data must have a specific condition (WHERE status=0 and id>20). How to export mysql database based on a where condition from phpMyAdmin or ...
0
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1answer
130 views

getting error while installing memcached_function

now i am working with memcached with mysql cluster 7.2 for that i am installed libevent-1.4.14b-stable.tar.gz memcached-1.4.5.tar.gz libmemcached-0.8.tar.gz then ...
1
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1answer
379 views

Using slash in MySQL database

I am using mysql with php Yii framework.When doing data modelling I came accross some doubt.I have a table for user details like this. CREATE TABLE IF NOT EXISTS `tbl_users` ( `id` int(11) NOT NULL ...
4
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1answer
4k views

Mysql Master-Master Replication Topologies on >2 machines

I have 3 Mysql servers that I would like to replicate: two (including the main server) are local and one is remote. Let's call my main server A, the secondary server B, and a remote, development ...
2
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1answer
327 views

select for update gives error on indexed column

here is my code: mysql_query("start transaction"); $q="select max(id) from test for update"; $r=mysql_query($q); $row=mysql_fetch_array($r); for ($k=0;$k<100000;$k++) { $q="insert into test values ...
0
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1answer
182 views

Sensible data management tool for importing and exporting of large data files

I am looking for some sensible suggestions on data management tools for large data files. I have been experimenting aith excel and access only to find that access has limitations on import files size ...
1
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1answer
153 views

what are the checklist when looking at MySQL database for first time?

What should I put on my checklist when I look at MySQL database for the first time? I would appreciate your help. Thanks.
1
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1answer
348 views

How to propagate a grandparent relationship throughout a tree?

I've got a MySQL table with columns id and parent, wherein each row has another row as a parent, except for some special root rows with parent=0. There are no cycles or broken relations. In order to ...
3
votes
3answers
1k views

Speed up search across multiple columns

We have a table: user_info (user_id,domain_id,first_name,middle_name,last_name,work_place,.,.,.) Now, we have a user search that search across three columns first_name,last_name and work_place. ...
1
vote
1answer
72 views

How can this data be joined?

Definition: table_A table_B id,description id,description,id_table_A Column id_table_A is a foreign key to the primary key of table_A and is not mandatory. Sample data: ...
1
vote
1answer
264 views

xtrabackup “failed to read metadata” [closed]

Doing a staging run setting up a new xtrabackup restore script I'm running into a somewhat cryptic error I can't readily google a solution for. I'm working with an incremental backup design. During ...
7
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2answers
3k views

MySQL CAST vs. CONVERT

Let's say that I have a VARCHAR (which contains numeric data) that I want to use for a simple computation (adding 10 to it). According to the MySQL documentation on CAST functions, I could accomplish ...
2
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1answer
333 views

Why is mysqlhotcopy slower compared to rsync?

My understanding is mysqlhotcopy works very similar to rsync. In one of our servers backing the database file using rsync takes about 15 minutes for 50GB data. Backing up the same data using ...
2
votes
1answer
744 views

How can I check if the keys are enabled on a MyISAM table?

I have a script, which populates 4 tables. It goes like this: Disable the keys on all the tables Populate the tables Enabled the keys back. The problem is that windows decided to reboot the ...
3
votes
2answers
9k views

MySql recommended hardware

Our company servers are currently hosted on a VPS and we've decided to move into dedicated servers. When choosing the best hardware for a DB server, what should we invest more resources: better CPU ...
2
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1answer
2k views

Can I mysqldump an entire database while using where='condition' on individual tables?

I have used mysqldump to dump an entire database, However, when I want to use --where=condition", on individual tables, I have dumped individual tables mysqldump --where='condition' mydb table ...
1
vote
1answer
303 views

Installing Sphinx on Mac OS with XAMPP

We have: Sphinx 2.0.3 Mac OS 10.6.8 XAMPP 1.7.3 (with MySQL 5.1.44) Here is PATH: user:sphinx-2.0.3-release user$ echo $PATH ...
3
votes
1answer
359 views

MySQL Config on Mac

I have a MacBook pro with 2.53 GHz Intel Core 2 Duo and 4GB DDR3 ram. I am running a huge database on my laptop with over 100 million records. I want to know : Which of the .cnf files is suitable ...
1
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1answer
838 views

How do you structure a database that allows for groups to be formed/added by users and also be a part of like facebook?

I'm new to databases and web development so a laymen explanation is best for the time being. I'm only in the data modeling phase so no need for specific code. I'm just trying to wrap my head around ...
1
vote
1answer
303 views

Why are these queries slow in some environments and not others? Can we fix their performance?

The following stored procedures in a MySQL 5.x environment: DELIMITER // CREATE PROCEDURE sp_belongs_to (IN schemaName VARCHAR(100), IN tableName VARCHAR(100)) BEGIN SELECT TABLE_NAME as ...
3
votes
1answer
222 views

MySQL chain replication

I have 3 servers A, B and C. What I want to do is replicate databases like this A->B->C, where A is replicating DB1 and DB2 to B and B is replicating those same databases to C, but I would also like ...
2
votes
1answer
164 views

Can not add list partitions

Following is the create table statement that is working as expected. But if I have a table without any partitions and if I try add partitions, it seems that I can not add more than 16 values in it. ...
4
votes
2answers
5k views

Performance settings for MyISAM tables - keep everything in memory

I have a 8-core MySQL server with 32 GB of RAM, holding 40 MyISAM tables (total: ~4GB of data). Since the databases size is several times smaller than the available memory, how can I make full usage ...
3
votes
1answer
1k views

MySQL ignoring index, index cardinality is the same as number of records in the table (?!)

Everyone, I could use an extra set of eyes on an issue we've come across. Here's what we're seeing: We're writing some code to migrate our messages to a new table called communications. We're ...
1
vote
1answer
110 views

How to determine if a column is the first part of an index?

Is there anyway to tell with SQL if an indexed column is the first part of an index. The closest thing looks to be information_schema.columns. But that seems to only tell me if it's a PRI or MUL key ...
1
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1answer
4k views

How to set a specific directory location for individual MySQL database?

Is it possible to set each database in MySQL to use a separate datadir? I'm running a userdir development (sandbox) server and would like to put the MySQL data files for the database(s) for that user ...
2
votes
2answers
162 views

How to index this table (a_level, b_level, item_id)

I have a table of items, each of it has an a_level, b_level, and an item_id. Any b_level is dedicated to only one a_level (example: b_level 14 is "child" of a_level 2 only) Lets say we have million ...
3
votes
3answers
2k views

Finding five-minute interval prior to current time

I want to find the five minute interval just before the current time. So if the current time is 8:43 I want to return 8:35 and 8:40. Here is the query that I have written and it is working as ...
4
votes
2answers
801 views

Read mysql config (my.cnf) using mysql console

I have a mysql server that is not under my control (I don't have ssh on that machine). I only have access to one database using mysql client. How can I have access to config options that are declared ...