Author: Editorial Team
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How G1 Garbage Collector (G1GC) Works
The G1 Garbage Collector (G1GC) is a modern, server-style garbage collector in Java, introduced in Java 7 (experimental) and fully supported from Java 8 onwards. G1GC is designed for large heaps (multiple gigabytes) and applications where low pause times are important, such as high-throughput server applications or real-time systems. It differs from traditional collectors (like…
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ROWID in Oracle
What is ROWID? ROWID is a pseudocolumn in Oracle that uniquely identifies the physical location of a row in a table. Characteristics of ROWID Feature Description Unique Each row has a unique ROWID within the database. Physical Address Contains data object number, datafile, block, and row position. Read-Only Cannot be updated or modified by users.…
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ROW_NUMBER()
What is ROW_NUMBER()? ROW_NUMBER() is an analytic function in Oracle SQL that assigns a unique sequential number to each row within a result set or partition, based on a specific order. Unlike the ROWNUM pseudocolumn (which is assigned before sorting), ROW_NUMBER() is assigned after the ORDER BY clause, which makes it more reliable for pagination,…
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ROWNUM in Oracle
What is ROWNUM? ROWNUM is a pseudocolumn in Oracle SQL that assigns a unique, sequential number to each row returned by a query result. Syntax You can also filter rows using ROWNUM: This fetches only the first 5 rows returned by the query. Important Behavior of ROWNUM Rule Explanation 1 ROWNUM is assigned after WHERE…
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HttpOnly Cookies
What Are Cookies? A cookie is a small piece of data stored on the client’s browser, sent by the server. It is used for various purposes like: Cookies are sent back and forth between the client and server with every request to a domain that set them. What Is an HttpOnly Cookie? An HttpOnly cookie…
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Refresh Token Grant Type in OAuth 2.0 (with Keycloak)
What is the Refresh Token Grant Type? The Refresh Token Grant Type is a mechanism that allows a client (application) to obtain a new access token using a refresh token without requiring the user to log in again. Why is It Needed? Components Term Description Authorization Server The identity provider that issues tokens (e.g., Keycloak)…
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JWT Usage in a React Application
When you use JWT in a React frontend, the typical workflow is: While this seems straightforward, security pitfalls often occur in how the token is stored and transmitted. An insecure implementation can expose sensitive information, allow attackers to impersonate users, or open your app to XSS/CSRF attacks. Best Practices for Secure JWT Handling in React…
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PIVOT Operator
Oracle SQL’s PIVOT clause allows you to transform row data into columns. It’s particularly useful when summarizing data across multiple categories, such as months, departments, or product types. 1. What Is Pivoting? Pivoting is the process of converting rows into columns to better analyze or report on grouped data. Example Scenario: Imagine you have a…
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PARTITION BY Clause
In Oracle SQL, the PARTITION BY clause is used with analytic (window) functions to divide the result set into groups or partitions, over which the analytic function is applied independently. This is similar to how GROUP BY works in aggregate functions, but with one major difference: GROUP BY collapses rows into one per group, whereas…
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DENSE_RANK() Function
The DENSE_RANK() function is an analytic (window) function in Oracle SQL that assigns ranks to rows in an ordered set without gaps in ranking values, even when there are ties. It is especially useful when you want to generate rankings with continuous numbers, even for rows with duplicate values. 1. Syntax Parameters: 2. Key Features…