Sql updating a row
The steps that the database uses to execute a statement greatly affect how quickly the statement runs.Many different ways of processing a DML statement are often possible.
Industry-accepted committees are the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO). includes many extensions to the ANSI/ISO standard SQL language, and Oracle Database tools and applications provide additional statements.
For example, the database could rewrite the entire query as a join of SET TRANSACTION NAME 'Update salaries'; SAVEPOINT before_salary_update; UPDATE employees SET salary=9100 WHERE employee_id=1234 # DML ROLLBACK TO SAVEPOINT before_salary_update; UPDATE employees SET salary=9200 WHERE employee_id=1234 # DML COMMIT COMMENT 'Updated salaries'; .
A session is a logical entity in the database instance memory that represents the state of a current user login to a database.
Specifies a condition to filter rows, producing a subset of the rows in the table.
A condition specifies a combination of one or more expressions and logical (Boolean) operators and returns a value of SELECT email, department_name FROM employees JOIN departments ON employees.department_id = departments.department_id WHERE employee_id IN (100,103) ORDER BY email; EMAIL DEPARTMENT_NAME ------------------------- ------------------------------ AHUNOLD IT SKING Executive statement retrieves the IDs of departments with location ID 1800.