Database deadlock can be defined as a situation when a data is locked by two or more data sessions. The lock on a particular data is requested by the database session. Each lock used on a database is entirely different from others. The time of the database sessions waiting to force the database lock is […]
What is Data Cardinality?
Cardinality in structured query language (SQL) can be defined as the mean of unique data value present in certain column. Cardinality is also known as data cardinality or attribute of database table. There are three types of data cardinality High Data Cardinality Normal Data Cardinality Low Data Cardinality Read: All about SQL CREATE USER Query […]
What is Cost Based Optimizer?
Query optimizer in RDBMS can be defined as a part of SQL program which is used to analyze the best way to run a SQL query. The query optimizers are used to improve the efficiency of the SQL statements. Related: SQL & .NET Interview questions and Answers What is Cost based Optimizer? Cost based optimizer […]
What is Clustered Index?
Clustered index in a database can be defined as the order in which rows present in a table are stored. Clustered indexes are used to accelerate the query searches in the database. It is easier to identify the data if rows are arranged in a proper manner. Read: Clustered & Non-clustered index in SQL Example […]
What is Blind SQL Injection?
The process of Blind SQL injection was first witnessed in 1998. Blind SQL injection is one of the most popular old bugs which are actively used till date. We know that the hacker use error messages from the database to check whether it is vulnerable or not. The error message thrown by the database will […]
Tuning SQL Index
In a database, SQL indexes are used to accelerate the query searching process. But using indexes will consume a lot of space and require regular maintenance. The regular maintenance on indexes will ensure the smooth running of database. This article will provide you some guidelines and tips to properly utilize indexes without any hassles. MySQL […]
SQL Three Valued Logic
The logic used by SQL is complicated because it uses three valued logic instead of two. Two valued logic is based on boolean algebra which return two value namely truth and fale. Boolean algebra can be operated using three basic operator namely AND, OR and NOT. If a unknown NULL value is used in boolean […]
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