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Database Programming
Databases are collections of tables that maintain and display information, often collaboratively; this information can be used for interaction with an application or gaining general knowledge. Questions about database engines and modifying or using them belong in this category.
8,803 Questions
What is the meaning of the data bus width?
In technology, the bus is used to carry data. The width of a data bus helps determine the amount of bytes that can be carried out each second.
Describe the database recovery process and the use of deferred-write and write-through techniques?
deferred-write: The transaction do not immediate update database, instead, only update log file. Then when transaction reach commit point, it will update the physical database.
write-through: The database is update right away during the transaction execution.
I'm also wondering about this. Is there anyone able to help us? I'm also wondering about this. Is there anyone able to help us? I'm also wondering about this. Is there anyone able to help us?
How your reset BIOS password from dell d620?
This information is intended for experienced users. It is not intended for basic users, hackers, or computer thieves. Please do not try any of following procedures if you are not familiar with computer hardware. I'll not be responsible for the use or misuse of this information, including personal injury, loss of data or hardware damage. So use it at your own risk.
A. By Using the Motherboard Jumper:
In most motherboards CMOS battery is soldered, which makes it difficult to remove the battery. In this case we use another method.
Almost all motherboards contain a jumper that can clear all CMOS settings along with the BIOS password. The location of this jumper varies depending upon the motherboard brand. You should read your motherboard manual to check its location. If you don't have the manual then look for the jumpers near the CMOS battery. Most of the manufacturer label the jumper as CLR, CLEAR, CLEAR CMOS, etc.
When you find the jumper, look carefully. There will be 3 pins and the jumper will be joining the center pin to either left or right pin. What you need to do, is remove the jumper and join the center pin to the opposite pin. e.g. if the jumper joins center pin to left pin, then remove it and join center pin to right pin. Now wait for a few seconds and then again remove the jumper and join the center pin to left pin.
Make sure to turn the PC off before opening the cabinet and resetting the jumper.
B. By Using Software:
I have found that BIOS/CMOS Password Recovery Tool is the most effective.:
BIOS/CMOS Password Recovery Tool is a program that works instantly to remove any lost or forgotten BIOS/CMOS password. Simply boot your PC to DOS and execute the program, and get access to forgotten BIOS/CMOS passwords in just seconds
BIOS/CMOS Password Recovery Tool Service
Can the FBI hack into your computer?
Technically yes its possible but the computer has to be on.
A:
They could, but even with a warrant allowing a hack (which I don't think has ever been asked for yet, much less granted), hacking your computer would be the most difficult way for them or any intruder to obtain your private information. There are lots of easier ways.
Hacking a computer -- coming in from the outside -- is relatively difficult, especially as your computer isn't set up to accept control from the outside (usually anyway). An outside hack would therefore be extremely technical.
Far easier would be to send you a Trojan that would load and run software that would accept their accessing and controlling your system from outside. This is feasible, but a heck of a lot of trouble.
If the FBI or any other law enforcement agency wants information from you, they won't bother with hacking. They'll either tap the line and trap your incoming and outgoing transmissions, or they'll obtain a search warrant and seize your computer. Or of course, both, if it's called for.
There is evidence that much of the traffic on the Internet is monitored (not neccesarily by the FBI), and some is examined carefully as part of the national threat assessment. However, as it's unlikley you're doing anything that could be considered a clear and present danger to the US, so this almost certainly won't apply to you.
In summary, the FBI could potentially hack into your system, but they are unlikely to go to all that trouble, when all they would have to do is secure a warrant to search, or an adminsitrative letter to tap.
How do you remove K9 software?
rofl, I solved this crap over a year ago... can't believe it's still giving people trouble. Alright, check it out -> you're able to install this over itself. Steps: 1. Go to: http://www1.k9webprotection.com/ -in fact even if you ctrl+alt+del and cancel the process, you can still get here from the error page that pops up when you want to connect to the internet. 2. Click Download K9 Today For Free 3. Fill out a name and e-mail address (make your own b/f hand if you don't have a personal one) 4. Click Request License -> you will be sent a license number and download link to the specified e-mail address. 5. Log-in to e-mail, download and install k9 over the previous version entering your license number, and choosing your own password for it (You don't need to know the password for the old copy, as far as it's concerned you are just reinstalling it). 6. You can now go to add/remove programs, delete the program, when prompted for a password, enter the one you just came up with and presto... ---- 7. Now for the kids who want to get smart w/ their parents, leave the k9 installed. It's a new version and only you know the password. That means no1 can check on where you've been so you don't care if the process it running - That's usually as far as a parent will check anywho, believing that it won't allow you to go to any wrong sites so long as it's up. ...And when/if they do try to check where you have been, you can watch while they get frustrated retyping their password wondering if they forgot it or typed it in wrong originally. ...And they can't accuse you of uninstalling something they thought was rock-solidly secure when it's right there, process still running and everything. On a more serious note, you should be aware that if you connect to the internet through a modem (like most households), whoever the person who set your connection up, (took it out of the box and connected/installed it on a computer, they have the ability to look up the traffic logs that went through that connection. So granted, by removing k9 it allows you to maneuver wherever you want, but so long as you live under their house, there still is the possibility that sum1 will be watching. If your parents are not tech savvy there is a way to change this by logging in with a default password. Find your modem brand/provider. Google how to access it (should just be http/// in search bar) and what the default username/password it (usually admin::password), and then go into the settings, change the password so only u can see the logs w/e you want - don't come crying if u f-something up that requires outside help to fix. However, if your parents weren't smart enough to change the password they prob don't know about the logs so it won't matter. Good Luck out there ;P Deviant
How do you read hyper terminal data to a file?
I have the same problem............
I want to read and write file but using Xmodem.....
Please help me out as soon as possible
What is the difference between buffer and register?
Both are storage device.register is inbuilt in processor.
both are temporary storage device.
register is located on the CPU and can hold only a small amount of data
buffer is an area of RAM and data are stored in advance
Could anyone List 10 places that databases are used?
Databases are used all over the place for many purposes. Databases take many forms as well. Whereever data is stored, one could argue that it's a database. So here are just a few places... 1) Schools use databases to track students, enrollment, grades, and report cards. 2) Banks use database to track money in accounts and transactions to those accounts. 3) Stores use databases to keep track of inventory and current prices. 4) Phone companies use databases to keep track of your phone usage and the accounting of charges to you. 5) Doctors use databases to track patients. 6) Electric companies use databases to track power usage and bill customers. 7) Internet service providers use databases (DNS servers) to convert the website addresses (like http:\\www.wikianswers.com\) to IP addresses such as 209.85.96.27, that computers use to find and communicate with other computers on the internet. 8) Online auction websites use databases to track the products being auctioned, the users, the bids, and the payment of those transactions. 9) Government uses databases to track tax payers and the payments they make, or fail to make. 10) WikiAnswers.com uses a database to track these questions and answers. There are many more uses for databases. Databases usually need to be customized for each use. There are generic databases that are intended for specific purposes that are available as prepackaged software, but most of the examples provided above are typically built as custom solutions. QuickBooks, TurboTax, Quicken, and Microsoft Money, are all examples of non-custom databases that are reusable for many people for similar purposes.
What advantages does SQL have over relational algebra?
Generally relational models are queried using relational algebras. SQL and XQuery are examples of relational algebras, with XQuery actually being a purer form of a relational algebra. : XQuery :: + Already exists and supports this extended relational model :: + Supports XPath :: + Supported by Oracle, IBM and Microsoft databases :: + Existing open source implementations for those who don't have it :: - Not yet a standard (but probably will be) :: - Not very easy to formulate :: - Immature development bindings usually resulting in DOM manipulation (not very efficient) :: - Difficult language to optimize which may result in poor performance :: - No developer community :: - No developer tools :: - It's currently a read-only language and the update additions are not focused on transactional systems : SQL :: + Millions of developers know (and love) it :: + Most repositories already support it :: + Supports PROJECTION, JOIN and UNION :: + Long established standard :: + Efficient language bindings with JDBC and ODBC :: + Lots of development tools :: - Need to specify and implement HIERARCHY ENUMERATION :: - Need to work around the multi-value problem with PROJECTION and SELECTION functions
New requests for the track over which the head currently resides can theoretically arrive as quickly as these requests are being serviced
In the context of relational databases, a foreign key is a referential constraint between two tables.[1] The foreign key identifies a column or a set of columns in one (referencing) table that refers to a column or set of columns in another (referenced) table. The columns in the referencing table must be the primary key or other candidate key in the referenced table. The values in one row of the referencing columns must occur in a single row in the referenced table. Thus, a row in the referencing table cannot contain values that don't exist in the referenced table (except potentially NULL). This way references can be made to link information together and it is an essential part of database normalization. Multiple rows in the referencing table may refer to the same row in the referenced table. Most of the time, it reflects the one (master table, or referenced table) to many (child table, or referencing table) relationship. The referencing and referenced table may be the same table, i.e. the foreign key refers back to the same table. Such a foreign key is known in SQL:2003 as self-referencing or recursive foreign key. A table may have multiple foreign keys, and each foreign key can have a different referenced table. Each foreign key is enforced independently by the database system. Therefore, cascading relationships between tables can be established using foreign keys. Improper foreign key/primary key relationships or not enforcing those relationships are often the source of many database and data modeling problems.
What are the disadvantages of dBase?
The original versions go back to the 1980s, so they are quite old. It was initially designed to work in DOS, as Windows did not exist then. I also pre-dates the internet's popularity and availability, so it did not have anything to facilitate the internet. The data types available are far more limited than modern databases. There is more work in formatting data types as a result. It has a query language and has the capabilities to do standard things like create reports, forms, queries, indexes and programs, but they are far more limited than modern databases. It has a limited amount of storage for fields and records, so it is not good for very large databases.
What are major differences between data warehousing and a relational database?
Data warehouse database
Designed for analysis of business measures by categories and attributes
Optimized for bulk loads and large, complex, unpredictable queries that access many rows per table.
Loaded with consistent, valid data; requires no real time validation
Supports few concurrent users relative to OLTP
OLTP database
Designed for real time business operations.
Optimized for a common set of transactions, usually adding or retrieving a single row at a time per table.
Optimized for validation of incoming data during transactions; uses validation data tables.
Supports thousands of concurrent users.
Difference between database file and flat file in DBMS?
Database file is one that is stored on a server and it is in the format that the database needs to read it. It is also stored in the database catalog. A flat file is one that is dumped from a database to import or export into another database or program. A flat file is fields of data separated by delimiters, which keep the fields separated for export/import.
Index funds are designed to track a specific benchmark. The benchmarks are often widely published, rebalance annually (also known as reconstitution), and focus on a specific section of the marketplace. Index funds are designed to be low-cost, transparent and come close to the performance of the benchmark (less expenses).
Fixed length fields are columns in a database table that always use a set amount of space for each row of data in the table. A fixed length field of 50 characters will always consume 50 characters for that field, regardless of how long the actual data in that field requires. Fixed length fields typically use more storage resources than variable length fields, but they are a bit faster for the processor to work with, since the length only needs to be determined once. Fixed length fields are appropriate for data where the length is constant. Some examples of fields that are good candidates for fixed length fields include Social Security Numbers, fixed length postal codes/ZIP Codes and telephone numbers (provided international data is unexpected.) Data that varies in length should be stored in a variable length field, as it will take less physical storage space and will not need to be truncated to remove extra spaces.
Suppose we have a Queue as follows: E -> D -> C -> B
We maintain a head pointer to E and a tail pointer to B.
To add an element, we make a new queue item (say A), we set B->next = A, and set tail = A.
To delete an element, we let a temp pointer to the head (say tempHead = head), set head = E->next and deallocate tempHead.
How does opening a file in Word differ from opening a file in Access?
Word is a word processing program. Letters, calendar creation. Access is a database--you store fields of data and records. So, when you open a file in Word, you are opening a document that you can print, modify, etc. When you open a file in Access, you're opening a database.
A type of data manipulation that doesn't affect the contents of a database is?
What is a type of data manipulation that doesn't affect the contents of a database?
# A feeling of discontent and resentment aroused by and in conjunction with desire for the possessions or qualities of another
# The object of such feeling: Their new pool made them the envy of their neighbors.
Source: Answers.com
