Tagged Questions
0
votes
1answer
106 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 ...
7
votes
1answer
233 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 ...
0
votes
0answers
38 views
How we can synchronize a MySQL database to an Oracle database?
How we can synchronize a MySQL database to an Oracle database?
The Oracle database is in secure zone that can only be accessed by application servers. We have multiple MySQL databases in different ...
1
vote
2answers
194 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
255 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
164 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 ...
0
votes
0answers
89 views
Moving database table data from MySQL to Oracle
I've developed a website with Drupal 7 running on standard PHP/MySQL server. Now there's a need to move it to server with Oracle database. I managed to set up testing environment with a fresh Drupal 7 ...
4
votes
1answer
120 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 ...
0
votes
0answers
365 views
Which is more scalable, Oracle RAC or MySQL Cluster? [closed]
I'm looking for information about both products and your experience would be a big help. I'm aware that Oracle RAC and MySQL Cluster uses different architecture and that Oracle RAC has single point of ...
3
votes
2answers
219 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 ...
6
votes
2answers
984 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
427 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
vote
2answers
201 views
Synchronising SQL tables in two locations
have a bit of conundrum a the minute.
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
99 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
185 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
227 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 ...
9
votes
1answer
266 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
71 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
263 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
284 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
838 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
588 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
599 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 ...
8
votes
3answers
3k 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
2k 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
218 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
282 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 ...
5
votes
1answer
819 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
412 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
845 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
395 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
235 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
573 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
297 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
507 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
291 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
109 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
1k 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 ...
0
votes
0answers
62 views
As Oracle Bought SUN is new version of MySQL realse? [closed]
I use OpenSource DBMS for my Work I want know if I continue using MySQL in future will encounter any problem as long as Oracle bought SUN? I don't know Oracle policy about releasing OpenSource MySQL ...
