What is generalization, aggregation and specification in database abstraction ?

The following link might be a start.
http://cs-exhibitions.uni-klu.ac.at/index.php?id=433

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Java + Database Abstraction

Hi
I have been programming in PHP for quite a while and it has database abstraction layers. Effectively this means that i can program using a MYSQL database, and then switch to Oracle by just changing one variable in a config file. There is no need to modify code or do anything else. From my reading Java's "solution" to this problem is JDBC (i think?).
Does java have a package pre-built that does this? From my understanding java has drivers, but i can't seem to find an overall library that gives me connectivity to the main databases and allows me to switch to a different one through a basic variable.
Any answers are appreciated
Edited by: amel_h on Sep 23, 2007 7:12 PM

That is different query syntax for a different database. If i switched drivers the query would fail, or would JDBC change such that it does not?You absolutely right: if you swapped drivers, the query would fail. The notion that JDBC gives you "vendor independence" is a big, fat myth. And that's because every vendor has their own SQL tweaks. For example, if you have a table with an auto generated PK field, how do you retrieve it? In Oracle you would use "dual", but with SQL Server, you would write "SELECT SCOPE_IDENTITY()". Even if a standard SQL statement works acrossyour target DBs, you may discover different versions of it run faster on different vendor's DBs.
My solution to this is to use a framework like Hibernate, which knows about these differences. In your code you don't embed SQL, but use Hibernate's query language which the framework translates.
If I wasn't doing this, my preferred solution would to:
1. Only call stored procedures and functions, or
2. Separate out the SQL and put it in a config file. Use different config files for different databases.

What is the link between PO and Requisition in database side

hello friends,
please can any one tell me that what is the link between PO and Requisition in database side. means after creating the requisition we will go for create the PO based on that requisition.
want to know that what is the link between both in database side.
Thanks in advance
krish.

Hi,
The link is at distribution level, between:
PO_DISTRIBUTIONS_ALL.REQ_DISTRIBUTION_ID
and
PO_REQ_DISTRIBUTIONS_ALL.DISTRIBUTION_ID
Hope it helps.

What is the best Practice to improve MDIS performance in setting up file aggregation and chunk size

Hello Experts,
in our project we have planned to do some parameter change to improve the MDIS performance and want to know the best practice in setting up file aggregation and chunk size when we importing large numbers of small files(one file contains one record and each file size would be 2 to 3KB) through automatic import process,
below is the current setting in production:-
Chunk Size=2000
No. Of Chunks Processed In Parallel=40
file aggregation-5
Records Per Minute processed-37
and we made the below setting in Development system:-
Chunk Size=70000
No. Of Chunks Processed In Parallel=40
file aggregation-25
Records Per Minute processed-111
after making the above changes import process improved but we want to get expert opinion making these changes in production because there is huge number different between what is there in prod and what change we made in Dev.
thanks in advance,
Regards
Ajay

Hi Ajay,
The SAP default values are as below
Chunk Size=50000
No of Chunks processed in parallel = 5
File aggregation: Depends largely on the data , if you have one or 2 records being sent at a time then it is better to cluster them together and send it at one shot , instead of sending the one record at a time.
Records per minute Processed - Same as above
Regards,
Vag Vignesh Shenoy

How can I determine what sites are being referenced within Central Admin Upgrade and Migration Manage Databases Upgrade Status?

When I go to Central Admin > Upgrade and Migration > Manage Databases Upgrade Status, I have 2 content databases which have the status:
Database is up to date, but some sites are not completely upgraded.
How can I determine which sites are not completely upgraded?

Manage Databases Upgrade Status will provide you all active and offline DB details, you can get same result
using below PowerShell cmdlet.
Get-SPDatabase and Get-SPContentDatabase will provide all active database/Content DB in Farm which include Service application db, central admin DB.
Get-SPDatabase | Format-Table Name, ID
Coming back to your question, if you find that there are some site are not completely upgraded then run below command and understand the cause if issue on specific DB.
Test-SPContentDatabase WSS_ContentDB_Name
If you find any missing file issue in DB then resolve these issue to upgrade content database.
(verify all customizations referenced within the content database are also installed in the web application. This cmdlet can be issued
against a content database currently attached to the farm, or a content database that is not connected to the farm )
Use the Upgrade-SPContentDatabase cmdlet
to resume a failed database upgrade or begin a build-to-build database upgrade against a SharePoint content database
Upgrade-SPContentDatabase WSS_Content
reference:
http://technet.microsoft.com/en-us/library/ff607813(v=office.15).aspx
http://technet.microsoft.com/en-us/library/ff607941(v=office.15).aspx
If my contribution helps you, please click Mark As Answer on that post and
Vote as Helpful
Thanks, ShankarSingh(MCP)

What are the differences between Oracle and other NoSQL database

Hi all,
I would like to know what the differences between Oracle and other NoSQL database are.
When and why should we use Oracle?
Is Oracle NoSQL database link with Big Data Appliance?
Can we use map-reduce on a single personal computer? How should we install Oracle NoSQL database to use map reduce on a single personal computer?
Do we also have eventual consistency with Oracle NoSQL database? Can we lose data if master node fails?
Are transactions ACID with Oracle NoSQL database? How can we prove it?
Thanks.

893771 wrote:
Hi all,
I would like to know what the differences between Oracle and other NoSQL database are.
When and why should we use Oracle?I suggest that you start here:
http://www.oracle.com/technetwork/database/nosqldb/overview/index.html
Is Oracle NoSQL database link with Big Data Appliance?Yes, Oracle NoSQL Database will be a component of the Big Data Appliance.
Can we use map-reduce on a single personal computer? How should we install Oracle NoSQL database to use map reduce on a single personal computer?Yes, I believe you can run M/R on a single computer. Consult the various pieces of documentation available on the web. You may run Oracle NoSQL Database on the same computer that you are running M/R on, but it is likely that they will compete for CPU and IO resources and therefore performance may suffer.
Do we also have eventual consistency with Oracle NoSQL database? Yes.
Can we lose data if master node fails?If you run Oracle NoSQL Database with the default (recommended) durability settings, then if the master fails, a new one will be elected and data is not lost.
Are transactions ACID with Oracle NoSQL database? How can we prove it?Yes, each operation is executed in an ACID transaction. The API has the concept of "multi" operations which allow the caller to perform multiple operations on sets of records with the same major key, but different minor keys. Those operations are also performed within a transaction.
Charles Lamb

What is aggregation and composition of objects?

Hi,
Please tell me What is aggregation and composition of objects?
What are the difference ? Is there anyother type of Object in java ?
Thankzx
MerlinRoshina

Hi,
Composition is developing a single , complex system by combining subparts.
Aggregation :
a composition that encapsulates (hides) the parts . User cant able to access the parts outside .
Association:
a composition of independently constructed and externally visible parts. User can access the parts outside .
To get more detailed information,
http://people.cs.vt.edu/~kafura/cs2704/basic.concepts.html
thanks,
nvseenu.

Okay, for a novice (iphone for dummies) what steps to take and in what order to identify specific problem and resolve issue of dropped calls and/or bad connections. I have a 3g iphone4, I think. Where is best place to find that information so I can veri

Okay, for a novice (iphone for dummies) what steps to take and in what order to identify specific problem and resolve issue of dropped calls and/or bad connections. I have a 3g iphone4, I think. Where is best place to find that information so I can verify.

You can call your wireless provider and talk to them about it.
You can restart your iphone, reset, your iphone and restore your iphone.

My iPhoto closed unexpectedly and now it says "Rebuilding the iPhoto Library database". What is going on and are my photos still going to be there?

My iPhoto closed unexpectedly and now it says "Rebuilding the iPhoto Library database". What is going on and are my photos still going to be there?

With the amount of information you've provided it's impossible to offer a solution. We can't see your computer so we need to know the details of your problem and setup, i.e.:
what version of iPhoto are you using?
what system version are you running?
what were you doing when iPhoto closed unexpectedly?
how big is your library, i.e. how many photos?
how long has the rebuilding been going on?
do you have a recent backup of the library made just prior to this occurring?
where is your library located?
did you apply any updates or upgrades just prior to the problem occurring?
are you running a "managed" or "referenced" library?
what type of Mac?
how much free space on your boot drive?

What is the difference between Aggregation and Composition with example

plz help me to find the difference between Aggregation and Composition with example

Dear [email protected]:
Get back to work.
August 4, 2007 stalin_gnana asked:
I would like to know the description about 'is a' ,'has a' ..relationship in java.plz reply me to the above doubt if known
August 8:
Can any one encounter the clarification on how and where Observer class and Observable interface can be applied..plz answer me
August 10:
May you find a solution on why not have the concept of pointer,opterator overloading,virtual function and destructor in java
(Also August 10):
I would desire to apprehend the brief description about usage of Singletone class and where it can be applied.plz help me
Today:
I am having the doubt of 'is there any relation among Delegation and composition'.if have,plz answer to regarding question.
And then this thread today too.
sniff sniff
I smell a lazy attempt at getting others to do one's homework for him.

Firefox is refusing to start. It says that my profile is missing, which it appears to be. Yet the way in which one goes about creating a new profile wont' work either. Anybody have a bloody clue what's going on and how to fix it?

Firefox is refusing to start. It says that my profile is missing, which it appears to be. Yet the way in which one goes about creating a new profile wont' work either. Anybody have a bloody clue what's going on and how to fix it?

AIR give you classes to detect an on-line or off-line status, it's in
this way for the sake of flexibility for instance what happens if you
only what to sync data only on Saturdays at 2 am? If it were done
automatically that'll be a problem. And it isn't so complicated.
You can download the SalesBuilder from AIR examples at www.adobe.com/devnet/air
it's an application that does everything you have in mind.
I don't understand your question abou file types.
An AIR app can communicate with almost every backend served tech
CF, .Net, PHP, RoR.
Sincerely,
Michael
El 14/05/2009, a las 8:48, IrishAIRMax <[email protected]> escribió:
>
I have to say that I'm loving the picture! well cool!
>
Sorry but I don't quiet understand. I thought AIR did the updating
automatically? I didn't realise the developer had to program the
logic of how the updates take place? Is it a case in most AIR apps
that when online the app updates the server and once every intervel
(of however long) the local SQLite DB is synced to the more updated
server DB. Then when offline the developer has to sense that the app
is offline and store a log manually of the updates without any help
from AIR itself, and then update once it comes online again?
>
Can AIR link to anything more than a database on the server side
apart from webservices, for example .as files or any other file types?
>
What type of server is a Flex app stored on, is it a specific Adobe
server rather than a Java or .NET server?
>
Thank you so much for your last comment!
IrishAIRMax
>

What is SQL Trace and How to Use it .

Dear Experts .
1.) May You Please tell me What is the Purpose of SQL-Trace and How to use it ?
2.) What is purpose of T-codes SE30 and ST22 ?
Please it is urgent ...
Regards : Rajneesh

Hi
SQL Trace transaction ST05: The trace list has many lines that are not related to the SELECT statement in the ABAP program. This is because the execution of any ABAP program requires additional administrative SQL calls. To restrict the list output, use the filter introducing the trace list.
The trace list contains different SQL statements simultaneously related to the one SELECT statement in the ABAP program. This is because the R/3 Database Interface - a sophisticated component of the R/3 Application Server - maps every Open SQL statement to one or a series of physical database calls and brings it to execution. This mapping, crucial to R/3s performance, depends on the particular call and database system. For example, the SELECT-ENDSELECT loop on a particular database table of the ABAP program would be mapped to a sequence PREPARE-OPEN-FETCH of physical calls in an Oracle environment.
The WHERE clause in the trace list's SQL statement is different from the WHERE clause in the ABAP statement. This is because in an R/3 system, a client is a self-contained unit with separate master records and its own set of table data (in commercial, organizational, and technical terms). With ABAP, every Open SQL statement automatically executes within the correct client environment. For this reason, a condition with the actual client code is added to every WHERE clause if a client field is a component of the searched table.
To see a statement's execution plan, just position the cursor on the PREPARE statement and choose Explain SQL. A detailed explanation of the execution plan depends on the database system in use.
Run time analysis transaction SE30 :This transaction gives all the analysis of an ABAP program with respect to the database and the non-database processing.
STEPS
Run time analysis transaction SE30
In Transaction SE30, fill in the transaction name or the program name which needs to be analyzed for performance tuning.
For our case, let this be ZABAP_PERF_TUNING
After giving the required inputs to the program, execute it. After the final output list has been displayed, PRESS the BACK button.
On the original SE30 screen, now click on ANALYZE button.
The percentage across each of the areas ABAP/ Database/System shows the percentage of total time used for those areas and load on these areas while running the program . The lesser the database load faster the program runs.
SQL Trace ST05
Starting the Trace:
To analyze a trace file, do the following:
Choose the menu path Test  Performance Trace in the ABAP Workbench or go to Transaction ST05. The initial screen of the test tool appears. In the lower part of the screen, the status of the Performance Trace is displayed. This provides you with information as to whether any of the Performance Traces are switched on and the users for which they are enabled. It also tells you which user has switched the trace on.
Using the selection buttons provided, set which trace functions you wish to have switched on (SWL trace, enqueue trace, RFC trace, table buffer trace).
If you want to switch on the trace under your user name, choose Trace on. If you want to pass on values for one or several filter criteria, choose Trace with Filter.
Typical filter criteria are: the name of the user, transaction name, process name, and program name.
Now run the program to be analyzed.
Stopping the Trace:
To deactivate the trace:
Choose Test Performance Trace in the ABAP Workbench. The initial screen of the test tool appears. It contains a status line displaying the traces that are active, the users for whom they are active, and the user who activated them.
Select the trace functions that you want to switch off.
Choose Deactivate Trace. If you started the trace yourself, you can now switch it off immediately. If the performance trace was started by a different user, a confirmation prompt appears before deactivation-
Analyzing a Sample trace data: PREPARE: Prepares the OPEN statement for use and determines the access method.
OPEN: Opens the cursor and specifies the selection result by filling the selection fields with concrete values.
FETCH: Moves the cursor through the dataset created by the OPEN operation. The array size displayed beside the fetch data means that the system can transfer a maximum package size of 392 records at one time into the buffered area.

Editing and Compling a Database Package from a file

Hi,
I'd like to know if there is a way to open and edit a database specification and body source code file from the filesystem, and also be able to compile this is SQL Developer.
Currently I am able to open the .pks and .pkb files and I get 'Compile' and 'Compile for Debug' icons. However, when I hit these buttons they appear to do nothing. No messages are displayed to say if the package is compiled successfully or unsuccessfully. What I have noticed though is that the code is executed and the package is created on the database but there is no feedback. If I 'complile' a package that I know is invalid, the package becomes invalid in the database and vice versa. But I have no way of knowing this until I check the package on the database.
If I am doing something wrong or there is another way to do this, then please let me know. I really want to be able to work on these files from the filesystem rather than the database.
SQL Developer 1.5.1 on Windows 2000.
Cheers,
Jon.

Jon,
The current SQL Dev support for file based development in this area isn't wonderful. However, the output of "compiling" a PL/SQL file with the compile button (ie running as script) is shown in the Script Output tab of the Log dockable window. If you have the window docked and the Script Output tab selected, then it will normally display the following where the package body is invalid:
Warning: execution completed with warning
PACKAGE BODY MY_PACKAGE_PKG Compiled.
To show the errors there, you will need to use something like after the CREATE OR REPLACE PACKAGE BODY statement:
SHOW ERRORS PACKAGE BODY MY_PACKAGE_PKG
The output doesn't always appear and the treatment of compilation errors is nowhere near as good as when compiling directly in the database where you can jump to the error location with a double click.
theFurryOne

Aggregation and Fragmentation

Hi Gurus,
what is meant by aggregation and fragmentation in OBIEE .Do we use these only when we want to improve the performance of the report if no in which type of scenarios when will go for these.Please any one help me with exact scenario.
Regards,
Rafi

Hi,
As per the below link
http://108obiee.blogspot.com/2009/01/fragmentation-in-obiee.html
In fragmentation after fragmenting the table in database and reimporting the tables and making the joins in Physical layer. we have to drag the table in BMM layer .
When we generating the report on channels table with channel id greater than 5 then how the biserver will go to the particular table(i.e.Channels_Other). How the biserver will follow the link between two tables(i.e. CHENNELS and CHENNELS_OTHERS) when fetching the data in the report.
In logical table source why we have to enable the option This source should be combined with other source at this level if we won’t enable this option what it will happens.
Thanks,
Edited by: Rafi.B on Aug 2, 2012 1:06 AM

What is the table and purpose?

let me know what is the table and its contents and purpose....i wil be thanks to you if i get answers

Table is a data repository in which all the master data and transactional data gets stored. All components/ data of SAP stored in Tables.
SAP Table Types
I. Transparent tables (BKPF, VBAK, VBAP, KNA1, COEP)
Allows secondary indexes (SE11->Display Table->Indexes)
Can be buffered (SE11->Display Table->technical settings) Heavily updated tables should not be buffered.
II. Pool Tables (match codes, look up tables)
Should be accessed via primary key or
Should be buffered (SE11->Display Table->technical settings)
No secondary indexes
Select * is Ok because all columns retrieved anyway
III. Cluster Tables (BSEG,BSEC)
Should be accessed via primary key - very fast retrieval otherwise very slow
No secondary indexes
Select * is Ok because all columns retrieved anyway. Performing an operation on multiple rows is more efficient than single row operations. Therefore you still want to select into an internal table. If many rows are being selected into the internal table, you might still like to retrieve specific columns to cut down on the memory required.
Statistical SQL functions (SUM, AVG, MIN, MAX, etc) not supported
Can not be buffered
IV. Buffered Tables (includes both Transparent & Pool Tables)
While buffering database tables in program memory (SELECT into internal table) is generally a good idea for performance, it is not always necessary. Some tables are already buffered in memory. These are mostly configuration tables. If a table is already buffered, then a select statement against it is very fast. To determine if a table is buffered, choose the 'technical settings' soft button from the data dictionary display of a table (SE12). Pool tables should all be buffered.
to know about structure. Please refer the link
http://help.sap.com/saphelp_nw2004s/helpdata/en/90/8d72fbb1af11d194f600a0c929b3c3/frameset.htm
Regards
Vivek
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What is generalization, aggregation and specification in database abstraction ?

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