Sybase 12.4.2 manual Cursors in transactions, 311

CHAPTER 8 Transactions and Versioning

Out of disk space

After you add space, the deletion resumes. When the delete transaction commits, the space becomes available for other deletions or insertions. If you do not need normally that much space in your database, you can drop the dbspace to regain the extra disk space for other purposes. Be sure you do so before inserting any data, so that you do not lose any data that Adaptive Server IQ might put in the new dbspace.

Running out of space during a deletion should not affect other query users.

If you run out of space, but do not have enough disk space to add another dbspace, you must shut down the database engine and then restart it, allowing the database to roll back. You can then delete the rows in smaller, separate transactions.

Note DROP TABLE and DROP DATABASE delete the table or database and all data in it without creating any version pages, so you do not need to add space to use these commands.

Cursors in transactions

A cursor allows you to return the results of a SELECT in the form of a data type called a cursor. A cursor is similar to a table, but has the additional property that one row is identified as the present, or current row. Various commands allow you to navigate through the rows of a cursor. For example, the FETCH command retrieves a row from the cursor and identifies it as the current row. You can step through all the rows in a cursor by calling this command repeatedly.

Cursors are of most use when you program procedures, or when you write applications that access a database using embedded SQL. They are also used by many front-end query tools. They are not available when using DBISQL interactively.

All Adaptive Server IQ cursors are read-only. You can write data, but the cursor does not see the write operation.

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