Database and SQL

Queries object class is meant to create the SQL compatible query statement with or without the help of Graphic User Interface (GUI) to define tables, store data and retrieves both data and information.

The record set of final SQL that relies upon preceding SQL statement, is collection of report-oriented information. This record set need be embedded in the report being produced.

Queries are the database objects used to retrieve, filter, and manipulate data from tables using SQL or graphical interfaces.

A table number is assigned to a table to uniquely identify it, especially when there are multiple tables in a document.

The standard SQL command to add new records to a table is 'INSERT INTO'. Other options like 'insert new' or 'add record' are not valid SQL syntax.

SQL Injection is a security vulnerability where an attacker inputs malicious SQL statements into entry fields, forcing the database to execute unintended commands. Using parameterized queries is actually a defense against SQL injection, not the vulnerability itself.

The UPDATE statement can modify multiple rows at once if the WHERE clause matches multiple records, or if no WHERE clause is specified at all. It does not delete rows, which is the job of the DELETE statement.

SQL stands for Structured Query Language, which is the standard programming language used to manage and manipulate relational databases.

Constraints (such as NOT NULL, UNIQUE, or CHECK) are typically defined on columns to restrict the type of data that can go into them. While some constraints can be defined at the table level (involving multiple columns), they are not applied to individual rows.

A primary key is a column or set of columns that uniquely identifies each row in a table, ensuring no duplicate records exist and providing a reliable way to reference specific entries.

INSERT, UPDATE, and DELETE are Data Manipulation Language (DML) commands because they modify data. Data Definition Language (DDL) commands include CREATE, ALTER, and DROP, which define or modify database structures.

The DROP command is used to completely remove a table structure and all of its data from the database. DELETE and TRUNCATE remove rows from a table but keep the table structure intact.

A subquery is a nested query placed inside another SQL statement (such as SELECT, INSERT, UPDATE, or DELETE) to return data that will be used by the outer query. It is not a command specifically designed to insert records.

The COUNT() aggregate function in SQL is used to return the number of rows that match a specified criterion. SUM() adds up numeric values, while ADD() and TOTAL() are not standard SQL aggregate functions for counting rows.

In SQL, the asterisk (*) wildcard character is used in a SELECT statement to specify that all columns should be retrieved from the target table.