rstriquer

Demand Some simple decimal calculations like 4.6 * 100 may lead in irregularities when dealing with numbers. Description During arithmetic operations like addition, subtraction, multiplication, and division, the numbers are manipulated according to the rules defined by the IEEE 754 standard. However, due to the finite precision of the representation, rounding errors may occur, leading to small discrepancies between the expected and actual results of computations. In simpler terms, the computer operates using powers of 2 (binary-based), so whenever we need to work with a number that cannot be exactly represented in binary (like 0.1, which is a base-10 fraction), it uses an approximation rather than an infinite number and is incapable of presenting the exact correct value. To prevent it we may use some libraries to prevent the problem. In Javascript and Typescript we have the BigNumbers library (and others). PHP has a built-in library for arbitrary-precision arithmetic called BCMath (Bin...

  Demand ALWAYS name unique key as "uq_{IndexName}" Description We use this convention to easily identify the source of the failure, especially in schema updates. When creating a CONSTRAINT we create its name starting with the string "uq", followed by the full name of the source table column used to build the index. Both separated by "_" (underline). Examples 1: CREATE TABLE customers ( 2:     id INT NOT NULL, 3:   name VARCHAR(100) NOT NULL, 4:    user_id INT NULL COMMENT 'if the customer have a system login it will be refernced here', 5:      PRIMARY KEY (id), 6: UNIQUE KEY `uq_user_id` (`user_id`), 6:      CONSTRAINT `fk_customers_user_id_users_user_id` 7:           FOREIGN KEY (`user_id`) 8:      REFERENCES `users` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION 9: ); Examples Explanation Here the  uq_user_id  is used to build a unique key...

Demand ALWAYS name forein keys constraints as "fk_{LocalTableName}_{LocalColumnName}_{DestinationTableName}_{DestinationFieldName}" Description We use this convention to easily identify the source of the failure, especially in schema updates. When creating a CONSTRAINT we create its name starting with the string "fk", followed by the full name of the source table, also called local table or child table, followed by the name of the column used in the source table to store the value to be searched for later in the target table, the name of the target table and finally the name of the field in the target table. All separated by "_" (underline). Examples 1: CREATE TABLE customers ( 2:     id INT NOT NULL, 3:   name VARCHAR(100) NOT NULL, 4:    user_id INT NULL COMMENT 'if the customer have a system login it will be refernced here', 5:      PRIMARY KEY (id), 6:      CONSTRAINT `fk_customers_user_id_users_user_id` 7:...

Demand Use "id_{context}" to name fields of external identification codes and "{context}_id" to internal ones. Description When creating a column in a table that reference an id (identification code) of a table located at the database you are dealing it should be named as "{Table Name}_id". When creating a column in a table that reference an id of a context external to the database you are dealing with  it should be named as "id_{Context Name}". Examples 1: CREATE TABLE customer ( 2:     id INT NOT NULL, 3:   name VARCHAR(100) NOT NULL, 4:     id_ssn COMMENT ' the United States, the Social Security number', 5:    user_id INT NULL COMMENT 'if the customer have a system login it will be refernced here', 6:      PRIMARY KEY (id), 7:     UNIQUE `uq_ssn` (`ssn`), 8:      CONSTRAINT `fk_customers_user_id_users_user_id` 9:           FOREIGN KEY (`user...