2
votes
0answers
59 views

How to distribute a given database between multiple DBMS on a LAN? [closed]

Given a Database D, i need to distribute it over different DBMS in a LAN. D will be split into tables, and each DBMS will store a given table. Here is a sketch of what i need to do : I also need to ...
0
votes
2answers
49 views

How to store a database table in multiple disks with assigned ratio?

I am going to deploy database tables to multiple disks. My database layout would be like following example: There are 3 tables (Customer, Order, Product) and 4 disks (disk_A, B, C, D). Customer: 5% ...
0
votes
0answers
29 views

Slow exporting SAP Data Services to MySQL (Oracle is faster)

We've a MySQL 5.1 server and we are trying to import data from SAP Data Services from another server. It works but it takes 3h! We tried to setup an Oracle XE server to test the same operation and it ...
0
votes
2answers
35 views

What are definer and invoker rights in database, Oracle and MysQL?

What are definer and invoker rights in database, Oracle and MysQL? I just don't get it
0
votes
2answers
120 views

Warning before issuing delete/update command in mysql/oracle , then executes

Is there any utility , function either in mysql /oracle that if i issue some delete/update command wrongly , a message must prompt at command_line* (if possible in ubuntu) asking whether "you sure to ...
1
vote
1answer
65 views

Mysql, sql server, oracle tables get too large [closed]

I hear a lot about things that, it is a lot cheaper to buy new harddisk than pay staff to come up with genius ideas how to save resources. But what I don't understand, is how these databases handle a ...
0
votes
1answer
78 views

retrieve data based on a condition

I have 2 tables, TA and TB: TA -------- id name 1 a 2 b 3 c 4 d 5 e 6 f TB -------- id p_id name 1 1 a 2 1 b 3 1 c 4 2 a 5 2 b 6 2 d I need : if ...
0
votes
0answers
25 views

Reliability of blobs in MySQL

I'm in the process of migrating an application working with Oracle to MySQL. That application stores data in the form of blobs, which can be pretty big. The Oracle production database is 60 Gb large ...
0
votes
2answers
113 views

Recommendation for RDBMS for large table [closed]

I have been asked for recommendation on the optimal RDBMS for a large amount of data. The largest table would contain 2TB of data. My own largest table is only 400GB (mysql, performs very well). The ...
0
votes
0answers
128 views

Efficient, up-to-date way to import an Oracle database into MySql

Here's the situation: I need to automatically merge data from an Oracle and a MySql server into a single, new MySql server. The merging will happen daily, and the resulting server will be hosted on a ...
-5
votes
0answers
57 views

Website is working very slowly [closed]

We have replication from Oracle to MySQL via Oracle Golden Gate. Yesterday because of some issues we have rebuilt the replication from Oracle to MySQL (this is called opal replication). Now our ...
0
votes
1answer
188 views

Object-oriented programming CRUD design pattern

At first I have posted this question at http://cstheory.stackexchange.com/questions/17170/object-oriented-programming-crud-design-pattern - that's because I think it's a subect question, and it can ...
8
votes
1answer
555 views

Is there an execution difference between a JOIN condition and a WHERE condition?

Is there a performance difference between these two example queries? Query 1: select count(*) from table1 a join table2 b on b.key_col=a.key_col where b.tag = 'Y' Query 2; select ...
3
votes
2answers
704 views

A database in MySQL is a schema in Oracle : I do not understand this statement

Please help me understand this statement: A database in MySQL is a schema in Oracle. I have just started to use Oracle and I find it different from other RDBMS softwares I have used like MSSQL, ...
1
vote
0answers
599 views

Migrating from Oracle to MySQL using WorkBench Migration Tool

I am currently migrating from Oracle to MySQL and I am going to use the migration tool in workbench to help me with the procedure. I have entered my source connection details as follows: Database ...
1
vote
1answer
236 views

Which Database to choose: MySQL or Oracle

I have an application generating time series data (32 channels, 22KHz, 6 secs) once a minute. These have to be stored in a database. At the moment I'm using MySQL with InnoDB tables ...
2
votes
1answer
667 views

Database Link from Oracle 10g on Windows over to MySQL database

Didn't see any answers on this subject so hoping for a miracle! :-) I've got an Oracle 10g database running on Windows Server 2003 and I'd like to create a database link to an external MySQL database ...
4
votes
1answer
148 views

Do isolation levels only apply to SELECTS and not UPDATES? [closed]

Scenario that might demonstrate different behavior for SELECTS depending on the isolation level: 1) 0:00 Thread A runs a query that returns 1000 rows that takes 5 minutes to complete 2) 0:02 Thread B ...
3
votes
2answers
450 views

SQL ANSI JOIN precedence

I have a query that looks like this: SELECT * FROM TBLA A LEFT JOIN TBLB B ON A.Col1 = B.Col2 RIGHT JOIN TBLC C ON B.Col3 = C.Col4 JOIN TBLD D ON C.Col5 = D.Col6 In which order ...
8
votes
2answers
3k views

For absolute performance, is SUM faster or COUNT?

This relates to counting the number of records that match a certain condition, e.g. invoice amount > $100. I tend to prefer COUNT(CASE WHEN invoice_amount > 100 THEN 1 END) However, this is ...
1
vote
1answer
853 views

Replicating data from Oracle to MySQL

I work with a vendor that does data analytics, and they currently receive a replication stream from some of our databases using a product called Goldengate (which is very expensive). Goldengate has ...
-1
votes
0answers
303 views

Synchronising SQL tables in two locations [closed]

We have a bit of a conundrum at the moment. ANSI SQL solutions please. We have two databases located at two different geographic locations and will be using the web for all traffic between the two ...
1
vote
1answer
161 views

What logical structure is used for storing rows in Oracle?

From the logical data separation point, there are tablespaces that consist of segments that consist of extend that consist of oracle blocks that consist of OS blocks. What logical structure actually ...
2
votes
2answers
283 views

simulate sequence on mysql in preparation for move to oracle

I've been developing an application against MySQL while a new development server has been slowly being set up. The new dev server will use oracle, and since we're getting close to it being ready, I ...
-8
votes
1answer
263 views

What are the edges of typical (or specific) paid databases like oracle of mysql compared to the free oness? [closed]

Note: I am building a startup. I am currently using mysql. I am pretty much stuck. Others recommend other free databases like mongodb. I am seriously considering paid one IF and only IF it gets better ...
10
votes
1answer
377 views

Disable explicit commits in JDBC, detect them in SQL, or put the database in a readonly state

Background: I'm working on http://sqlfiddle.com (my site), and am trying to prevent one avenue of abuse possible there. I'm hoping that by asking about a problem I'm currently addressing, I don't ...
-1
votes
1answer
76 views

Index Proposals

As a theoretical database question, if you are asked 'which indexes would you propose and why?' are the answers from primary, clustering and secondary index? How would we know if we should introduce ...
-1
votes
1answer
297 views

Important distinctions between DBMSs [closed]

DBA is a career I'm strongly considering after school, but my limited experience mostly involves some PL/SQL Oracle web programming, some basic PHP/MySQL web pages, and some queries in SQL Server. ...
0
votes
2answers
460 views

Commercial database systems versus open source database systems [closed]

Can anyone tell me what are the reasons for buying a commercial database system and not using an open-source free version? The reason for my question is that: Commercial systems cost upwards of ...
-1
votes
2answers
1k views

Data Base Administration Oracle vs MySql? [closed]

I have worked with MSSQL for a while now, but now we want to try to move to some open source for a specific part of the company's products or explore Oracle if possible. What would you say are the ...
2
votes
3answers
712 views

Move Oracle data to and from MySQL with the help of PHP?

My application is in PHP which by default uses MySQL db. I have connected MySQL & Oracle dbs with PHP. Now I want to move data from Oracle db into Mysql db through PHP. Is it possible to do? Is ...
6
votes
2answers
888 views

Database for building a realtime analytics system

I want to build a system similar to Google Analytics (only used for internal use, less traffic and less feature), and mainly focus on Real time counting of unique URI visit/PV by different ...
9
votes
3answers
4k views

Where can I find example databases for MySQL, SQL Server and Oracle?

I want to experiment with the 3 large database management systems. For this purpose it would be cool to have the same database (the same tables, etc.) for each of those. Where can I find sql scripts ...
3
votes
4answers
4k views

Synchronizing data between MySQL and Oracle databases?

I want to sync data between Oracle & MySQL databases. What is the best possible way to achieve this? Are there any tools/software available? This is not a one-time but an ongoing operation. The ...
1
vote
0answers
313 views

Oracle Flashback Archive aka Total Recall in MySQL

What would you suggest as a replacement system to achieve the same functionality of Oracle Flashback Archive aka Total Recall in other DBMS, in general or specifically in MySQL or MariaDB? ...
0
votes
1answer
363 views

which DBMS should i go for? [closed]

I am interested in learning a DBMS. As a beginner which DBMS should i go for ? I know few DBMS by name like Oracle,Sql Server,My Sql . How are these DBMS different from each other ? As a beginner ...
6
votes
1answer
1k views

MySQL or Oracle Associate Certification?

I have 15+ years in software development and 7+ in web development, and I want to get a certification in another area, like DBA. I have 7+ years of experience like MySQL developer. Which is better for ...
2
votes
2answers
542 views

Logical schema development and migration tool for different physical schema available including triggers and stored procedures?

We are planning to support for our application another rdbms (oracle). At the moment we are design our database schema with the MySQL-Workbench. For every new database version we have schema ...
6
votes
2answers
1k views

Is DB2 more reliable and stable compared to PostgreSQL or MySQL?

Always i was using MySQL or PostgreSQL for my projects such as Web/Desktop apps. I had data loss few times and thanks to old backup i was always up and running. But for a recent project for Airport, ...
3
votes
1answer
517 views

Will {fn concat} work without issue in MySQL, SQL Server and Oracle?

According to this (quite old) article the principle behind ODBC escape sequences is that The ODBC driver reads the escape sequence and translates it into the DBMS-specific syntax before sending ...
3
votes
3answers
245 views

Effect of Oracle on MySQL

While the future of MySQL is unknown, I haven't had time to keep up with the known effects that Oracle has had on MySQL since it was bought from SUN. Have there been changes of note, either by Oracle ...
3
votes
3answers
694 views

Convert Oracle query to MySQL

I've just tried to convert this update command, which is Oracle sql, to MySQL with SQLWays and it failed with the following error: You can't specify target table 'animal_table' for update in FROM ...
6
votes
3answers
390 views

Is there a need to keep refreshing the indexes from time-to-time?

This question is common for all the database products I use, viz. SQL Server, MySQL, Oracle and PostgreSQL. I have created a fresh database and the tables, at present, have no records. I have created ...
4
votes
3answers
572 views

Is Oracle DB immune to the InnoDB deadlocks found in MySQL?

It seems odd to me that MySQL would not handle this internally: "Deadlock found when trying to get lock; try restarting transaction" Does Oracle DB work around this issue? After all, Oracle owns ...
3
votes
4answers
341 views

How to get a column A which has the smaller column B grouping by column C?

I'd like to get the ID of a dataset for each category (my grouping column) which has the smallest "order" column. Here a set of data to explain my thoughts: CREATE TABLE DATAS ( ID INT(2) , ...
1
vote
1answer
119 views

Is there any tool to convert Oracle commands to MySQL?

Is there any tool which I can use to convert Oracle commands to mysql commands?
2
votes
8answers
2k views

What database front end do you use? [closed]

What database front end do you use? It should let you manage databases, tables, indexes and ideally even data records. And it should ideally be free so we can all use it too. Databases that it could ...