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[Figure: Example of correspondence between schemas and database spaces]
Base table
A base table consists of columns and rows. Figure: Base table format example is a base table format example. In this
figure, one row consists of the data for one product. The data of a single row consists of several columns. A column
corresponds to a data item. The data for one product (one row) consists of the four data items (columns): ITMNO,
PRODUCT, STOCKQTY, and WHCODE.
The base table configuration is defined by schema definition statements. Table definitions in a schema definition
define the data items that form each base table. A table definition defines the following items:
· Table name
· Column
· Table constraint
Table name
A table name is the name assigned to each table.
The table name is used to specify the table to be the object of a data manipulation. The table name is also used when
adding or deleting a table definition. This table definition specifies the table definition information subject to deletion or
addition processing.
Column
A column definition contains the following definitions for a column that forms a base table.
Column name:
A column name is the name assigned to each column. The column name is used to specify the column to be
processed by a data manipulation. The column name is also used when altering a schema definition to
indicate the column to be altered.
Column data type:
The data of each column has a type, such as character, numeric or data-and-time type.
Column default value:
The column default value defines the value to be set if the column data is omitted when data is inserted or
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