Cursors for updating single parent dating riverside connecticut
By extending SQL, PL/SQL offers a unique combination of power and ease of use.You can manipulate Oracle data flexibly and safely because PL/SQL fully supports all SQL data manipulation statements (except ), transaction control statements, functions, pseudocolumns, and operators.A transaction is a series of SQL data manipulation statements that does a logical unit of work.For example, two statements might credit one bank account and debit another.NEXTVAL WHERE first_name = 'Lynette' AND last_name = 'Smith'; -- Display end value of CURRVAL SELECT employees_seq. PUT_LINE ('Ending sequence value: '
You can use CREATE TABLE employees_temp AS SELECT employee_id, first_name, last_name FROM employees; CREATE TABLE employees_temp2 AS SELECT employee_id, first_name, last_name FROM employees; DECLARE seq_value NUMBER; BEGIN -- Display initial value of NEXTVAL -- This is invalid: seq_value := employees_seq. CURRVAL, 'Morgan', 'Smith'); -- Because NEXTVAL values might be referenced by different users and -- applications, and some NEXTVAL values might not be stored in the -- database, there might be gaps in the sequence -- The following uses the stored value of the CURRVAL in seq_value to specify -- the record to delete because CURRVAL (or NEXTVAL) cannot used in a WHERE clause -- This is invalid: WHERE employee_id = employees_seq. CURRVAL INTO seq_value FROM dual; DELETE FROM employees_temp2 WHERE employee_id = seq_value; -- The following udpates the employee_id with NEXTVAL for the specified record UPDATE employees_temp SET employee_id = employees_seq.If you want precise control over query processing, you can declare an explicit cursor in the declarative part of any PL/SQL block, subprogram, or package.You must declare an explicit cursor for queries that return more than one row.A cursor can take parameters, which can appear in the associated query wherever constants can appear.The formal parameters of a cursor must be on a cursor parameter.
As the following example shows, you can initialize cursor parameters to default values.