I was helping out some colleagues of mine with an SQL problem. Mainly they wanted to move all the rows from table A to table B (both tables having the same columns (names and types)). Although this was done in Oracle 11g I don't think it really matters. Their initial naive implementation was something like BEGIN INSERT INTO B SELECT...
Could not find this term very easily on google. I assume it's the ability to patch a DBMS with an update without stopping service. Is this correct? If not, please guide me. Thanks in advance. jbu ...
Please enumerate the procedure in which a visual basic program can access a database using data control and Active x data object (ADO)? ...
Hi again, I am currently analyzing a wikipedia dump file; I am extracting a bunch of data from it using python and persisting it into a PostgreSQL db. I am always trying to make things go faster for this file is huge (18GB). In order to interface with PostgreSQL, I am using psycopg2, but this module seems to mimic many other such DBAPIs...
Hi people, Does anyone know a situation where a PostgreSQL HASH should be used instead of a B-TREE for it seems to me that these things are a trap. They are take way more time to CREATE or maintain than a B-TREE (at least 10 times more), they also take more space (for one of my table.columns, a B-TREE takes up 240 MB, while a HASH would...
I am writting an application which needs to periodically (each week for example) loop through several million records ina database and execute code on the results of each row. Since the table is so big, I suspect that when I call SomeObject.FindAll() it is reading all 1.4million rows and trying to return all the rows in a SomeObject[]....
I develop a product with a custom database configuration. I use ADO.NET with System.Data.Odbc.OdbcConnection for it. To make some differences between the databases is there a simple solution to detect the current DBMS of a connection. ...
What is the command to drop all tables in SQLite? Similarly I'd like to drop all indexes. ...
What does a null value in DBMS represent? Is it unassigned or inapplicable or zero or blank space? ...
How do you represent the sub queries in SELECT and WHERE clauses? ...
I'm not very experienced with DBMS systems so I need some advice about which DBMS to use for storing RSS feeds. The DBMS must be available on Linux and be free. I have some experience with MySQL but I am unsure if it performs fast enough to handle the storage and updates of hundreds of thousands of xml documents. ...
Hi! Can anyone give a 'practical' task for my coursework? I am completly run out of ideas. Everything seems to be done before me. To be honest i am a beginner in that field and have little expireince. I d'like to do something little but useful for somebody. Ideally, it should be one with help of which i can learn more about one of wi...
I'd be curious to find out how the major databases compare in terms of popularity. How much of the market does Oracle have? How much does MS SQL have? MySQL, PostGre, ...? How does this breakdown in the smaller markets (e.g. small web apps, large web apps, huge corporate services,...)? I'm looking for statistics here. Not impression...
I would like to programmatically export my Procedures / Functions and Packages into individual files (as a backup) and using Oracle 9.2. The closest solution i found was using DBMS_METADATA.GET_DDL , but how do i output the CLOB to a text file, without losing any parts (due to length or indentation) ? Or maybe do you have other solut...
Take this query: SELECT * FROM MyTable WHERE MyColumn = 'SomeValue' ORDER BY SomeFakeQualifier.MyColumn DESC It seems that SqlServer just ignores the qualifier in this case. Should you add a JOIN, then it will consider it. This really isn't an issue, until you want to make your queries viable across DBMS vendors. Oracle, f...
Hi all, Is Projection and selection are vertical and horizontal slicing respectively? please tell the difference between projection and selection Projection --> for selecting the columns of table Selection ---> to select the rows of table so, Selection is horizontal slicing? ...
Can anybody let me know that what is the datatype for NULL? Some body is tellin that NULL doesnt hav any data type. some body is telling that NULL is Character type. Please let me know that what is the datatype of NULL. Thanks in advance. ...
I am working on an open source project which can use a number of DBMS' as backend. So far we supports SQL Server 2005 and SQL Server 2008 but we would also like to support some additional databases including some file based DBs. Note: The file based databases must work on a 64-bit platform, so MS Access is not an option as there is no 6...
I'm currently on my way to write a web application implementing the MVC and well reducing complex things. Yet I've been pondering for a few hours what to do for future database systems like Oracle, PostgreSQL, Firebird, etc. Then again to implement these adapters in the logic is what gets me, should I just trigger-happy it with tons of...
What is the best DBMS to use in iphone when there is huge data that is to be sorted and searched often. I though to use sqlite but it has many complexities. as when a table is created once it doesn't allow to change its structure, No way to define relationship etc. Can any one guide me wat way to follow Regards, ...