Database Objects
Tables · Tables are the basic unit of data storage in an Oracle Database. Data is stored in rows and columns. · You define a table with a table name, such as employees , and a set of columns. You give each column a column name, such as employee_id , last_name , and job_id ; a datatype, such as VARCHAR2 , DATE , or NUMBER ; and a width. · The width can be predetermined by the datatype, as in DATE . If columns are of the NUMBER datatype, define precision and scale instead of width. · A row is a collection of column information corresponding to a single record. · You can specify rules for each column of a table. These rules are called integrity constraints. One example is a NOT NULL integrity constraint. This constraint forces the column to contain a value in every row. Type of Table Description Ordinary (heap-organized) table This is the basic, general-purpose type of table. Its da