31Jan/17

Index

January 31, 2017RDBMSduplicate-index, index, unique-indexDreamMaker

Some specific steps are perform by the oracle engine each time whenever user access record from the data base table. It will first search for a specific table on the hard diskRead More…

27Jan/17

VIEW

January 27, 2017RDBMSdatabase-view, readonly-view, updatable-view, viewDreamMaker

A view is a logical entity which is created from the base table. The main purpose of creating a view is to provide security over the database table. In some cases whenRead More…

27Jan/17

DUAL TABLE

January 27, 2017RDBMSdual, dual-tableDreamMaker

A dual table is oracle’s in built table. It can be used for arithmetic calculations. We can retrieve data from the dual table but cannot insert the data. It has only singleRead More…

25Jan/17

DEFAULT VALUE

January 25, 2017RDBMSdefault-value, insert_intoDreamMaker

Insert statement is used to insert record into the table but we have to specify each value for the column list. There are cases in which some value gets repeated for majorityRead More…

25Jan/17

USER CONSTRAINTS

January 25, 2017RDBMSbusiness-constraints, constraints, data-integrity-constraints, i/o-constraints, user-constraintsDreamMaker

We can use describe command to view logical structure of the table. It displays table structure including column name, data type, size & not null constant. It does not provide information aboutRead More…

24Jan/17

Constraint Using ALTER TABLE

January 24, 2017RDBMSalter-table, business-constraints, constraints-using-alter-table, data-integrity-constraints, dropping-constraints, i/o-constraints, modify-constraintsDreamMaker

In our post “I/O Constraint” and “Business Constraints” we had seen how we can add constraints at the time of table creation using Create table command. If you have not read ourRead More…

11Dec/16

Business Constraint

December 11, 2016RDBMSbusiness-constraints, check-constraint, data-integrity-constraints, i/o-constraintsDreamMaker

Business constraint defines business rules or business policy. Each organization have their specific rules about the data store. Check constraint can be used to define business rules. Check Constraint When constraint cannotRead More…

11Dec/16

I/O Constraints

December 11, 2016RDBMSbusiness-constraints, data-integrity-constraints, foreign-key, i/o-constraints, not-null, primary-key, unique-keyDreamMaker

I/O Constraints Constrains that control data insertion and data retrieval speed are known as I/O (Input-Output) constraints. It includes the following constraints. Primary Key Foreign Key Unique Key Not Null Primary KeyRead More…

11Dec/16

Data Integrity Constraints

December 11, 2016RDBMSbusiness-constraints, data-integrity-constraints, i/o-constraintsDreamMaker

Sometimes we need to provide some restriction on the data for security and data integrity reason. We must ensure that only valid and complete data should be stored into the database. OracleRead More…

05Nov/16

ALTER TABLE

November 5, 2016RDBMSalter-table, create-table, updateDreamMaker

ALTER TABLE command is used to modify table structure. We can add new column, remove existing column or change data type and size by using alter table command. If records are availableRead More…