SQL Articles - Page 10 of 12

What is NoSQL?As per the official Wiki definition: “A NoSQL (originally referring to “non SQL” or “non relational”) database provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relation databases (RDBMS). It encompasses a wide variety of different database technologies that were developed in response to a rise in the volume of data stored about users, objects and products, the frequency in which this data is accessed, and performance and processing needs. Generally, NoSQL databases are structured in a key-value pair, graph database, document-oriented or column-oriented structure.Over decades ... Read More

SQL (Structured Query Language) is a computer language which is used to interact with an RDBMS (Relational Database Management System). It is basically a method of managing, organizing, and retrieving data from a relation database. In SQL, two important concepts are used namely, function and procedure. A function calculates the results of a program based on the inputs provided, whereas a procedure is used to perform some tasks in a specific order. There are many other differences between functions and procedures, which we will discuss in this article. What is Function? A function, in the context of computer programming languages, ... Read More

PL/SQL stands for “Procedural Language extension to SQL” . It is the mixture of SQL and Procedural features provided by programming language. It was developed by Oracle Corporation in the late 1980s as procedural extension language for SQL and the Oracle relational database.PL/SQL programs consists of blocks that can be nested and a block structure look likes this −DECLARE    -- it contains declaration statements BEGIN    -- It contains executable statements EXCEPTIONS    -- It contains exception handling statements END;ExampleIn PL/SQL single-line comments begin with double hyphen(--) and Multi-line comments begin with a slash-asterisk ( /* ) and end ... Read More

The tag executes an SQL statement that does not return data; for example, SQL INSERT, UPDATE, or DELETE statements.AttributeThe tag has the following attributes −AttributeDescriptionRequiredDefaultsqlSQL command to execute (should not return a ResultSet)NoBodydataSourceDatabase connection to use (overrides the default)NoDefault databasevarName of the variable to store the count of affected rowsNoNonescopeScope of the variable to store the count of affected rowsNoPageExampleTo start with basic concept, let us create a simple table Employees table in the TEST database and create few records in that table as follows −Step 1Open a Command Prompt and change to the installation directory as follows ... Read More

The different types of functions in Oracle are −Oracle String FunctionsOracle Numeric FunctionsOracle Date FunctionsMore details about these functions are given as follows −Oracle String FunctionsThe following are the Oracle String Functions −ASCII(str)This function returns the ASCII or numeric value of the first word in the string str provided. If it is an empty string, it returns 0. For example:SQL> SELECT ASCII('Apple'); +---------------------------------------------------------+ | ASCII('Apple') | +---------------------------------------------------------+ | 65 | +---------------------------------------------------------+ 1 row in set (0.00 sec)This returns the ASCII value of A i.e. 65 as it is the first character in the string.CONCAT(str1, str2…..strn)This function returns the string that ... Read More

When a SQL statement is executed in Oracle, the temporary context area is created. This area contains all the relevant information relating to the statement and its execution. The cursor is a pointer to this context area and allows the PL/SQL program to control this area.There are two types of Cursors.Implicit CursorsExplicit CursorsLet us begin with Implicit Cursors −Implicit CursorsWhenever an SQL statement is executed, the implicit cursors are automatically created. This happens if there is no explicit cursor for the particular statement. Implicit cursors cannot be controlled by the programmers.There are many different attributes for Implicit Cursors. Some of ... Read More

Packages are SQL procedures, functions, variables, statements etc. that are grouped into a single unit. Many different applications can share the contents of a package, as it is stored in the database.Parts of a PackageThe following are the parts of a package in Oracle −Package SpecificationThe package specifications contains information about all the procedures, functions, variables, constants etc. stored inside it. It has the declaration of all the components but not the code.All the objects that are in the specification are known as public objects. If there is any object that is not available in the specification but is coded ... Read More

Yes, you can open SQL console and execute the statement −LOAD (, ...);This SQL query will load or unload entire column into or from main memory. Its load status is TRUE or FALSE. The table's load status is PARTIALLY.

This can be created using following SQL query −CREATE USER TEST_122 PASSWORD Pass123$$

>Create View View_name as Select Col1,Col2 From Table_name;In the above SQL statement, you are creating a view that contains Col1 and Col2 from the table.Table Name − Emp_InfoExampleIdEmplNameEmpluserEmplpasswordJoining_Date1Employee 1Emp1Emp1Pwd9/11/20162 Employee 2Emp2 Emp2Pwd   16/08/20153Employee 3Emp3Emp3Pwd15/09/20164Employee 4Emp4   Emp4Pwd  3/07/20145Employee 5Emp5Emp5Pwd10/09/20126Employee 6Emp6  Emp6Pwd   1/10/2013                                                                                               To create a view, which contains only 3 columns you have to write->Create View View_EmpInfo As Select Id, EmplName,Joining_Date  From Emp_Info;This view can be used by users to get Id, EmplName, and Joining_date.