Writing Basic SQL Queries¶ As part of this section we will primarily focus on writing basic queries. Standard Transformations Overview of Data Model Define Problem Statement – Daily Product Revenue Preparing Tables Selecting or Projecting Data Filtering Data Joining Tables – Inner Joining Tables – Outer Performing Aggregations Sorting Data Solution – Daily Product Revenue …
Inserting Data¶ Let us see how to insert the data into the table. We need to use INSERT clause to insert the data. Here is the sample syntax. INSERT INTO <table_name> (col1, col2, col3) VALUES (val1, val2, val3) If we don’t pass columns after table name then we need to specify values for all the …
Creating Table¶ Before getting into action with respect to basic DML and queries or CRUD operations, we need to prepare tables.At this time we have not covered DDL yet. All database operations related to managing tables come under DDL. For now, let’s just create the table by copy pasting below CREATE TABLE statement. We will …
CRUD Operations¶ Let us get an overview of CRUD Operations. They are nothing but DML and queries to read the data while performing database operations. CRUD is widely used from application development perspective. C – CREATE (INSERT) R – READ (READ) U – UPDATE (UPDATE) D – DELETE (DELETE) As part of the application development …
Database Operations – Overview¶ Let us get an overview of Database Operations we typically perform on regular basis. They are broadly categorized into the following: DDL – Data Definition Language CREATE/ALTER/DROP Tables CREATE/ALTER/DROP Indexes Add constraints to tables CREATE/ALTER/DROP Views CREATE/ALTER/DROP Sequences DML – Data Manipulation Language Inserting new data into the table Updating existing …
Tables as Relations¶ Let us understand details about relations and different types of relationships we typically use. In RDBMS – R stands for Relational. In the transactional systems, tables are created using normalization principles. There will be relations or tables created based on relationships among them. Here are the typical relationships among the tables. 1 …
