PCWorkshops

  Is Airtable A No-SQL Database? Short answer: ·          From a user point of view, yes — Airtable behaves like a NoSQL system. ·          From a technical point of view, no — it’s not a pure NoSQL database. User / practical perspective ·          You don’t write SQL ( Do the SQL Course ) You don’t design schemas like in SQL databases You work with flexible records, links, and fields You query data via a REST API , not SQL Because of this, people often treat Airtable like a NoSQL database . Technical / internal perspective Airtable supports: Tables Relations (linked records) o     Structured fields Do the SQL Course This strongly suggests a relational (SQL-like) model under the hood , even though Airtable doesn’t expose SQL to users. So internally, it’s relational , not NoSQL. Do the SQL Cour...

  Two Ways MySQL Workbench Can Draw an ERD Do the course A. Reverse Engineer (from an existing database) Menu: Database → Reverse Engineer Workbench connects to your DB, reads all schema metadata, and draws the ERD automatically. B. Create a Model Manually (forward engineer) Menu: File → New Model You create tables visually, and Workbench generates SQL from your ERD. Do the course NB! Make sure that all primary and foreign keys are identified, because the diagram will be drawn based of primary and foreign key definitions.   Do the course

  How You Generate an ERD in SSMS (SSMS = SQL Server Management Studio)  Do the course Expand your database in SSMS. Right-click  Database Diagrams . Select  New Database Diagram . Choose the tables you want to include. SSMS automatically draws the ERD. Do the course

  What is a Data Warehouse? Do the course Have you ever thought about where all the information generated across industries is kept? Every day, the world produces billions of megabytes of data, and that number continues to rise. In this lesson, we’ll explore how data warehouses store this information in a centralized location and allow organizations to use it effectively. Let’s dive straight in. What is a Data Warehouse? Do the course A Data Warehouse (DWH) is a key element of a business intelligence ecosystem, designed to help users carry out analytical tasks and examine large datasets. It brings together information from a variety of sources—including transactional systems, application logs, and more. A DWH often acts as the organization’s authoritative source of data. You can think of it as a dedicated environment that supports management by holding vast amounts of historical information. By evaluating this data, a DWH enables companies to make more informed and...

s-Key In a data warehouse , an S-key usually refers to a Surrogate Key . Definition: Surrogate Key (S-Key) A surrogate key is an artificial, system-generated identifier used in a data warehouse dimension table. It has no business meaning —its only purpose is to uniquely identify a row. Common forms: Integer identity column (1, 2, 3…) UUID (less common) Hash key (in Data Vault) Why Surrogate Keys Are Used Surrogate keys solve several issues that arise in data warehouses: 1. Slowly Changing Dimensions (SCD) They allow tracking multiple versions of a dimension (e.g., customer address changes). Each version gets a different surrogate key, even if the business key (e.g., customer_id) is the same. 2. Stability Business keys can change (e.g., product codes, emails). Surrogate keys do not. 3. Performance Integer surrogate keys join faster than long strings or composite business keys. 4. Simplifies integration Multiple source systems may...

Delete vs Truncate in MySQL and MS SQL Server DELETE DELETE is a DML command. The DELETE statement is executed using a row lock; each row in the table is locked for deletion. We can specify filters in where clause It deletes specified data if a "where" condition exists. Delete activates a trigger because the operations are logged individually. Slower than truncate because it keeps logs. Rollback is possible. TRUNCATE TRUNCATE is a DDL command. TRUNCATE TABLE always locks the table and page but not each row. Cannot use the WHERE condition. It removes all the data. TRUNCATE TABLE cannot activate a trigger because the operation does not log individual row deletions. Faster performance-wise, because it doesn't keep any logs. Rollback is possible. DELETE and TRUNCATE both can be rolled back when used with TRANSACTION (TRUNCATE can be rolled back in SQL Server, but not in MySQL ). if there is a PK with auto increment, truncate will reset the counter Learn SQL with us at PCWorks...