SQL sequences specifies the properties of a sequence object while creating it. An object bound to a user-defined schema called a sequence produces a series of numerical values in accordance with the specification used to create it. The series of numerical values can be configured to restart (cycle) when it runs out and is generated in either ascending or descending order at a predetermined interval. Contrary to identity columns, sequences are not linked to particular tables. Applications use a sequence object to access the next value in the sequence. The application has control over how sequences and tables interact. A sequence object can be referred to by user applications, and the values can be coordinated across various rows and tables....
The SQL WITH clause was introduced by Oracle in the Oracle 9i release 2 database. The SQL WITH clause allows you to give a sub-query block a name (a process also called sub-query refactoring), which can be referenced in several places within the main SQL query....
Structured Query Language is a standard Database language that is used to create, maintain, and retrieve the relational database. In this article, we will discuss this in detail about SQL. Following are some interesting facts about SQL. Let’s focus on that....
There are a lot of real-world scenarios where a query for finding the nth salary will be really useful. Considering finding the second-highest salary in SQL, we have one sample table....
The difference between the having and where clause in SQL is that the where clause cannot be used with aggregates, but the having clause can....
Data Lake is the concept where all sorts of data can be landed at a low cost but exceedingly adaptable storage/zone to be examined afterward for potential insights. It is another advancement of what ETL/DWH pros called the Landing Zone of data. Only presently we are looking at ALL sorts of information independent of construction, structure, metadata, etc. One of the thoughts behind Data Lake is that presently innovation has made it conceivable to store ALL information that a firm generates/buys (prior it would be a case where the firm HAD to select the pertinent information and store it in a structured distribution center)....
The ER model is a very important concept in DBMS, and it is used for the modeling of the logical view of the system from a data perspective. The entity, Entity Set, and Entity Type all these terms are very important concepts of ER Model. In this article, we will understand the difference between them....
Prerequisite : Physical and Logical Data Independence...
Joins are used to combine two or more different tables based on a common field between them with the help of this we can easily retrieve the data from multiple tables. So, In this article, we are going to discuss the JOIN Operation, and Subquery in detail. Let’s start with the JOIN operation....
1. Tuple Relational Calculus (TRC) : A tuple relational calculus is a non-procedural query language that specifies to select of the tuples in a relation. It can select the tuples with a range of values or tuples for certain attribute values etc. The resulting relation can have one or more tuples....
