Database Programming

E.F. Codd, the famous mathematician has introduce 12 rules for the relational model for databases commonly known as Codd's rules. The rules mainly define what is required for a DBMS for it to be considered relational , i.e., an RDBMS. There is also one more rule i.e Rule00 which specifies the relational model should use the relational way to manage the database. The rules and their description is as follows:- Rule 000:A RDBMS system should be capable of using its relationalfacilities (exclusively) to manage the database. Rule 1: The information rule : All information in the database is to be represented in one and only one way. This is achieved by values in column positions within rows of tables. Rule 2 : The guaranteed access rule : All data must be accessible with no ambiguity.This is achieved in the RDBMS by using the primary key concept. Rule 3: Systematic treatment of null values : The DBMS must allow each field to remain null. The null can be stored in any field of any datatype. Rule 4: Active online catalog based on the relational model : The authorized users can access the database structure by using common language i.e SQL. Rule 5: The comprehensive data sublanguage rule : The system must support at least one relational language that has simple syntax and transaction management facilities. It can be used in the application as well as in the RDBMS systems. Rule 6:The view updating rule : All views must be updatable by the system. Rule 7: High-level insert, update, and delete: The system is able to insert, update and delete operations fully. It can also perform the operations on multiple rows simultenously. Rule 8: Physical data independence : Changes to the physical storage structure must not require a change to an application based on the structure. Rule 9: Logical data independence : Changes to the logical level (tables, columns, rows, and so on) must not require a change to an application based on the structure. Rule 10: Integrity independence : All the Integrity constraints like primary key, uniques key etc must be specified separately from application programs and stored in the catalog. Rule 11: Distribution independence : The distribution of portions of the database to various locations should be invisible to users of the database. Rule 12: The nonsubversion rule : If the system provides a low-level (record-at-a-time) interface, then that interface cannot be used to subvert the system, for example, bypassing a relational security or integrity constraint. Note:- Any database management system which fulfills 6 or more than 6 rules can be considered as the RDBMS. Maulin Thaker Codd's Rule There are 13 (0 to 12) rules which were presented by Dr. E.F.Codd ,in June 1970,in ACM (Association of Computer Machinery) Rule 0. Relational Database management “A relational database management system must use only its relational capabilities to manage the information stored in the database”. Rule 1. The information rule All information in the database to be represented in one and only one way, Namely by values in column positions within rows of tables. Rule 2. Logical accessibility This rule says about the requirement of primary keys. Every individual value in the database must be logically addressable by specifying the name of table, column and the primary key value of the row. Rule 3. Representation of null values The DBMS is required to support a representation of "missing information and inapplicable information" (for example, 0 'Zero' is different from other Numbers), This type of information must be represented by the DBMS in a systematic way (For example Null Character ). Rule 4. Catalog Facilities The system is required to support an on line, in line, relational data access to authorized users by using their Query language. Rule 5. Data Languages. The system must support a least one relational language (It may support more than one relational language) that (a) has a linear syntax, (b) can be used in two ways and within application programs, (c) supports data operations security and integrity constraints, and transaction management operations (commit). Rule 6. View Updatability All views that are theoretically updatable must be updatable by the system. Rule 7. update and delete. The system must support INSERT, UPDATE, and DELETE operators. Rule 8. Physical data independence Changes to the physical level (how the data is stored, whether in arrays or linked lists etc.) must not require a change to an application based on the structure. Rule 9. Logical data independence Changes made to tables to modify any data stored in the tables must not require changes to be made to application programs. Logical data independence is more difficult to achieve than physical data independence. Rule 10. Integrity Constraints Integrity constraints must be specified separately from application programs and stored in the catalog. It must be possible to change such constraints when they are unnecessarily affecting existing applications. Rule 11. Database Distribution The RDBMS may spread across more than one system and across several networks, however the tables should appear in same manner to every user like local users. Rule 12. The Non Subversion rule If the system provides a low-level interface, then that interface cannot be used to weaken the system (e.g.) bypassing a relational security or integrity constraint.

To solve a problem with booting which requires access to the network to solve the problem Safe Mode boots the OS with minimum configuration and can be used to solve problems with a new hardware installation or problems caused by user settings

the data communication is like in which all working of networks through which we communicate each others.

in Unix: the datatype is "Date"

in C++: the datatype is "char"

Standards in computer science engineering include ISO and Six Sigma. Certifications in these fields include C++. Microsoft Certified Systems Engineer, J+ and COBOL.

The ability to reuse the same code at different places in the program with out coping it.

BECAUSE IT IS, MOFOS.

Database is vulnerable because it collects, maintains, and disseminates information. These data essentially include exploitability and potential impact. Example of this is the Open Source Vulnerability Database.

3 different database projects

foreign key constraint defines a column or combinations of columns whose values match the primary key of another table.

u can keep on changing it

Applications of interfaces to the DBMS are created, allowing users to manage and gain access to data within the database. Connolly & Begg (2001, pp 4) state 'a database application is simply a program that interacts with the database at some point in its execution'.

Interfaces of a DBMS provides functionality with the ability to add, delete, update and retrieve data, process data to complete tasks, produce reports and manage data.

Thomas Connolly (2001). Database Systems: A Practical Approach to Design, Implementation and Management . Third. ed: Addison Wesley.

We can only feed 1 and can take 2 out from the decision box.

In C and C++ you may use isc_interprete to get a human-readable description of the error.

If you use IBPP API, it thorws exceptions containing a description of error.

Record can mean the actual disc that the music was stored, or it could be the album itself.

Yours in helping,

Apeman

allan allan identify the four parts of edp

Amendment means to make certain changes in a bill, law or constitution. But it is famously known for adding, removing & making changes in a constitution.

Computer Aided Instruction.

A folder is a directory. Folders can be inside other folders, and so can files...

The main similarity of storage devices and memory is that both are used for storing documents, files and images. They all come in different storage capacity.

well it's a measure of space in a technological database (i.e. a harddrive) some relations are 1024MB = 1GB 1MB = 1024KB 1MB = 1024000 bytes How much space a virus that slows down your computer takes = all your MB

IsNull(Exp1,Exp2) for example select isnull(TelNo,'Missing') from table1

SQL means Structured Query Language. It is a programming language which is mainly used for maintaining databases. Excel is one of the application developed by Microsoft to do calculations, graphs using spreadsheets.

1024 MB = 1 GB