Nonstop Database, HiRDB Version 9 Description
The cells in a table's horizontal plane constitute rows; the cells in the vertical plane constitute columns. The row is the unit for performing operations on a table. Each row consists of data entries from one or more columns. Each column is given a column name. When an operation is performed on a table, you identify the position of an item in a row by its column name. The following figure shows the structure of a table.
Figure 3-4 Example of a table
CREATE TABLE STOCK (PCODE CHAR(4), PNAME NCHAR(8), COLOR NCHAR(1) PRICE INTEGER, SQUANTITY INTEGER);
A data type must be specified for each column and for each attribute comprising an abstract data type. Data types are classified broadly as predefined data types and user-defined data types. A predefined data type is provided by HiRDB. A user-defined data type is defined by a user as needed. The following table lists the available data types.
Table 3-3 Available data types
Classification | Data type | Data format | |
---|---|---|---|
Predefined | Numeric data | INTEGER | Integer |
SMALLINT | Integer | ||
LARGE DECIMAL | Fixed point | ||
FLOAT | Double-precision floating point | ||
SMALLFLT | Single-precision floating point | ||
Character data | CHARACTER | Fixed-size character string | |
VARCHAR | Variable-size character string | ||
National character data | NCHAR | Fixed-size national character string | |
NVARCHAR | Variable-size national character string | ||
Mixed character data | MCHAR | Fixed-size mixed character string | |
MVARCHAR | Variable-size mixed character string | ||
Date data | DATE | Date | |
Time data | TIME | Time | |
Time-stamp data | TIMESTAMP | Precision for time-stamp data in floating-point seconds | |
Date interval data | INTERVAL YEAR TO DAY | Date interval | |
Time interval data | INTERVAL HOUR TO SECOND | Time interval | |
Large object data | BLOB | Binary data string | |
Binary data | BINARY | Binary data string | |
Boolean data | BOOLEAN | Boolean value | |
User-defined | Abstract data type | -- | -- |
--: Not applicable
Data types are specified when a table is created with the CREATE TABLE of the definition SQL. The data type for an attribute comprising an abstract data type is specified with the CREATE TYPE of the definition SQL. For details about abstract data types, see Section 3.5 Expansion into an object relational database.
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