HP 3000 Manuals HP 3000 Manuals
Chapter 12 Programming with LONG Columns
LONG columns in ALLBASE/SQL enable you to store a very large amount of
binary data in your database, referencing that data via a table column
name. You might use LONG columns to store text files, software
application code, voice data, graphics data, facsimile data, or test
vectors. You can easily SELECT or FETCH this data, and you have the
advantages of ALLBASE/SQL's recoverability, concurrency control, locking
strategies, and indexes on related columns.
You can use LONG columns in an application program to be preprocessed or
with ISQL. This discussion focuses on application programming concerns.
As you will see, great flexibility is provided so that you can custom
design your application.
The chapter highlights methods of implementing LONG columns in your
database as follows:
* General Concepts.
* Restrictions.
* Defining LONG Columns with the CREATE TABLE or ALTER TABLE
command.
* Defining Input and Output with the LONG Column I/O String.
* Putting Data into a LONG Column with INSERT.
* Retrieving LONG Column Data with SELECT, FETCH, or REFETCH.
* Changing a LONG Column with UPDATE [WHERE CURRENT].
* Using the LONG Column Descriptor.
* Removing LONG Column Data with DELETE or DELETE WHERE CURRENT.
* Coding Considerations.
For every DDL and DML command that can be used with LONG columns,
examples are included with discussion of related considerations. These
examples pertain to the same logical table (PartsTable) and set of
columns. In contrast to other examples in this chapter, PartsTable is a
hypothetical table created and altered in this chapter. Refer to
the ALLBASE/SQL Reference Manual which contains complete syntax
specifications for using long columns.
Table 12-1. Commands You Can Use with LONG Columns
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| | |
| DDL Operations | DML Operations |
| | |
---------------------------------------------------------------------------------------------
| | |
| ALTER TABLE | INSERT |
| | |
| CREATE TABLE | UPDATE [WHERE CURRENT] |
| | |
| | SELECT |
| | |
| | FETCH |
| | |
| | REFETCH |
| | |
| | DELETE [WHERE CURRENT] |
| | |
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