What is a Schema?
A Schema is a collection of certain database objects, such as tables, indexes, and views, all of which are owned by a user account. A schema is a logical collection of database objects. Ideally a...
View ArticleRules for Naming Tables and Database Objects
Below is the standard naming rules of Oracle objects. The length of table name must be at least one character, and maximum of 30 characters. First character in a name must be a letter. After the first...
View ArticleWhat is the difference between trigger and stored procedure?
Triggers are executed automatically when something changes in the database (like new record inserted, deleted etc). Stored procs are executed when they are called. Related Posts:Triggers and Stored...
View ArticleTransaction Control Statements in Oracle
Transaction control statements are ussued to either save the modified data or to undo the changes if they were made in error. Until the data has been permanently saved to the table, no other users will...
View ArticleWhat is Data Dictionary?
Database: Any collection of information; technically, a collection of computer data in related records treated as a single unit. Data Dictionary is the information about database. The data dictionary...
View ArticleTO_DATE Function in ORACLE
There are number of functions intended to convert values of one datatype to another datatype. Some of the most commonly used are TO_NUMBER, TO_CHAR, and TO_DATE. Consider the SQL statement below:...
View ArticleDifference between Primary Key, Unique Key Surrogate Key
Primary Key: A column in a table whose values uniquely identify the rows in the table. A primary key value cannot be NULL. Unique Key: Unique Keys are used to uniquely identify each row in an Oracle...
View ArticleProcedure and Function Difference
A FUNCTION is always returns a value using the return statement. A functions can be useed in select or update or delete statement while procedure can’t. A PROCEDURE may return one or more values using...
View ArticleDataTypes Used in Oracle
Most datatypes fall under one of the general categories of numeric, character, or date. Character Character datatpes are also known as text or string datatypes, and they include CHAR(n) and...
View ArticleEquality Joins
Equality Joins is the most commonly used joins. This is also called inner joins and is based upon two (or more) tables having equivalent data stored in a common column. Such joins are called Equality...
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