Oracle C++ Call Interface Programmer's Guide

Processing of SQL Statements
Control Statements
CREATE TYPE person_t AS OBJECT (
name VARCHAR2(30),
ssn VARCHAR2(12),
address VARCHAR2(50))
CREATE TABLE person_tab OF person_t
OCCI applications treat transaction control, connection control, and system control
statements like DML statements.
Data Manipulation LanguageSQL Statements
Queries
Data manipulation language (DML) statements can change data in database tables.
For example, DML statements are used to perform the following actions:
■ Insert new rows into a table
■ Update column values in existing rows
■ Delete rows from a table
■ Lock a table in the database
■ Explain the execution plan for a SQL statement
DML statements can require an application to supply data to the database by using
input (bind) variables. Consider the following statement:
INSERT INTO dept_tab VALUES(:1,:2,:3)
Either this statement can be executed several times with different bind values, or an
array insert can be performed to insert several rows in one round-trip to the server.
DML statements also enable you to work with objects in the Oracle database, as in
the following example, which inserts an instance of type person_t into the object
table person_tab:
INSERT INTO person_tab
VALUES (person_t(’Steve May’,’123-45-6789’,’146 Winfield Street’))
Queries are statements that retrieve data from tables in a database. A query can
return zero, one, or many rows of data. All queries begin with the SQL keyword
SELECT, as in the following example:
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