Updating reference tables mysql hp laserjet p4015x problem updating firmware

When you use names to refer to elements of databases, you are constrained by the characters you can use and the length that names can be.

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We're telling My SQL not to allow a row for an employee to be removed from theemployees table without first removing the rows of data for the employee in the employees_telephone table.

These are capabilities found in some other databases but not in My SQL.

Such features include triggers, stored procedures, and views.

Text displayed in italic letters represent text that should be replaced with the specific names related to the database (e.g., column with the name of the column).

ALTER [IGNORE] TABLE table ADD [CONSTRAINT [symbol PRIMARY KEY [USING index_type] (column,...) | ADD [CONSTRAINT [symbol]] UNIQUE [INDEX|KEY] index [USING index_type] (column,...) | ADD [CONSTRAINT [symbol]] FOREIGN KEY [index] (column,...) [REFERENCES table (column, ...) [ON DELETE ] [ON UPDATE ]]CREATE TABLE employees (emp_id INT AUTO_INCREMENT PRIMARY KEY, tax_id CHAR(12), emp_name VARCHAR(100)) ENGINE = INNODB; CREATE TABLE employees_telephone (emp_id INT, tel_type ENUM('office','home','mobile'), tel_number CHAR(25)) ENGINE = INNODB; ALTER TABLE employees_telephone ADD FOREIGN KEY emp_tel (emp_id) REFERENCES employees (emp_id) ON DELETE RESTRICT; SHOW TABLE STATUS FROM human_resources LIKE 'employees_telephone' G *************************** 1.

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We're telling My SQL not to allow a row for an employee to be removed from theemployees table without first removing the rows of data for the employee in the employees_telephone table.These are capabilities found in some other databases but not in My SQL.Such features include triggers, stored procedures, and views.Text displayed in italic letters represent text that should be replaced with the specific names related to the database (e.g., column with the name of the column).ALTER [IGNORE] TABLE table ADD [CONSTRAINT [symbol]] PRIMARY KEY [USING index_type] (column,...) | ADD [CONSTRAINT [symbol]] UNIQUE [INDEX|KEY] index [USING index_type] (column,...) | ADD [CONSTRAINT [symbol]] FOREIGN KEY [index] (column,...) [REFERENCES table (column, ...) [ON DELETE ] [ON UPDATE ]]CREATE TABLE employees (emp_id INT AUTO_INCREMENT PRIMARY KEY, tax_id CHAR(12), emp_name VARCHAR(100)) ENGINE = INNODB; CREATE TABLE employees_telephone (emp_id INT, tel_type ENUM('office','home','mobile'), tel_number CHAR(25)) ENGINE = INNODB; ALTER TABLE employees_telephone ADD FOREIGN KEY emp_tel (emp_id) REFERENCES employees (emp_id) ON DELETE RESTRICT; SHOW TABLE STATUS FROM human_resources LIKE 'employees_telephone' G *************************** 1.In the following example we first insert an employee in the employees table, then add her home telephone number to the second table, and then attempt to delete her from the first table: INSERT INTO employees VALUES(1000,'1','Paola Caporale'); INSERT INTO employees_telephone VALUES(1000,2,' 39 343-'); DELETE FROM employees WHERE emp_id = 1000; ERROR 1451 (23000): Cannot delete or update a parent row: a foreign key constraint fails (`human_resources`.`employees_telephone`, CONSTRAINT `employees_telephone_ibfk_1` FOREIGN KEY (`emp_id`) REFERENCES `employees` (`emp_id`) ) As you can see, we cannot delete the employee from the employees table and leave the stray row of data in the employees_telephone table.We have to delete the data in employees_telephone first, before deleting the related data from employees.Some of the statements in the table are not covered here because they are more appropriately discussed in other chapters.For example, the administrative statements for setting up user privileges are dealt with in Chapter 11, "General My SQL Administration." Chapter 12, "Security," provides further details on what privileges are available and what they allow.Do these omissions mean that My SQL isn't a "real" database system?Some people think so, but in response I'll simply observe that the lack of these capabilities in My SQL hasn't stopped large numbers of people from using it.

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