The abort tran on log full option determines the fate of a transaction that is running when the last-chance threshold is crossed in the log segment of the specified database. The default value is false, meaning that the transaction is suspended and is awakened only when space has been freed. If you change the setting to true, all user queries that need to write to the transaction log are killed until space in the log has been freed.

Setting the allow nulls by default option to true changes the default value of a column from not null to null, in compliance with the SQL standards. The Transact-SQL default value for a column is not null, meaning that null values are not allowed in a column unless null is specified in the create table or alter table column definition. allow nulls by default true reverses this.

While the auto identity option is set to true (on), a 10-digit IDENTITY column is defined in each new table that is created without specifying either a primary key, a unique constraint, or an IDENTITY column. The column is not visible when you select all columns with the select * statement. To retrieve it, you must explicitly mention the column name, SYB_IDENTITY_COL, in the select list.

To set the precision of the automatic IDENTITY column, use the size of auto identity column configuration parameter.

Though you can set auto identity to true in tempdb, it is not recognized or used, and temporary tables created there do not automatically include an IDENTITY column.

For a report on indexes in a particular table that includes the IDENTITY column, execute sp_helpindex.

While the dbo use only option is set to true (on), only the database's owner can use the database.

When the ddl in tran option is set to true (on), you can use certain data definition language commands in transactions. If ddl in tran is true in a particular database, commands such as create table, grant, and alter table are allowed inside transactions in that database. If ddl in tran is true in the model database, the commands are allowed inside transactions in all databases created after ddl in tran was set in model.

Warning!

Data definition language (DDL) commands hold locks on system tables such as sysobjects. Avoid using them inside transactions; if you must use them, keep the transactions short.

Using any DDL commands on tempdb within transactions may cause your system to grind to a halt. Always leave ddl in tran set to false in tempdb.

The following commands can be used inside a user-defined transaction when the ddl in tran option is set to true:

• alter table - clauses other than partition and unpartition are allowed

• create default

• create index

• create procedure

• create rule

• create schema

• create table

• create trigger

• create view

• drop default

• drop index

• drop procedure

• drop rule

• drop table

• drop trigger

• drop view

• grant

• revoke

The following commands cannot be used inside a user-defined transaction under any circumstances:

• alter database

• alter table...lock

• alter table...partition

• alter table...unpartition

• create database

• disk init

• dump database

• dump transaction

• drop database

• load transaction

• load database

• select into

• truncate table

• update statistics

In addition, system procedures that create temporary tables or change the master database cannot be used inside user-defined transactions.

The identity in nonunique index option automatically includes an IDENTITY column in a table's index keys, so that all indexes created on the table are unique. This database option makes logically nonunique indexes internally unique, and allows these indexes to be used to process updatable cursors and isolation level 0 reads.

The table must already have an IDENTITY column for the identity in nonunique index option to work, either from a create table statement or by setting the auto identity database option to true before creating the table.

Use identity in nonunique index if you plan to use cursors and isolation level 0 reads on tables with nonunique indexes. A unique index ensures that the cursor will be positioned at the correct row the next time a fetch is performed on that cursor. If you plan to use cursors on tables with unique indexes and any isolation level, you may want to use the unique auto_identity index option.

For a report on indexes in a particular table that includes the IDENTITY column, execute sp_helpindex.

The no free space acctg option suppresses free-space accounting and execution of threshold actions for the non-log segments. This speeds recovery time because the free-space counts are not recomputed for those segments.

The no chkpt on recovery option is set to true (on) when an up-to-date copy of a database is kept. In these situations, there is a "primary" and a "secondary" database. Initially, the primary database is dumped and loaded into the secondary database. Then, at intervals, the transaction log of the primary database is dumped and loaded into the secondary database.

If this option is set to false (off), the default condition, a checkpoint record is added to a database after it is recovered when you restart Adaptive Server. This checkpoint, which ensures that the recovery mechanism will not be rerun unnecessarily, changes the sequence number and causes a subsequent load of the transaction log from the primary database to fail.

Setting this option to true (on) for the secondary database causes it not to get a checkpoint from the recovery process so that subsequent transaction log dumps from the primary database can be loaded into it.

The read only option means that users can retrieve data from the database, but cannot modify any data.

Setting the select into/bulkcopy/pllsort option to true (on) enables the use of writetext, select into a permanent table, "fast" bulk copy into a table that has no indexes or triggers, using bcp or the bulk copy library routines, and parallel sort. A transaction log dump cannot recover these minimally logged operations, so dump transaction to a dump device is prohibited. After non-logged operations are completed, set select into/bulk copy/pllsort to false (off) and issue dump database.

Issuing the dump transaction statement after unlogged changes have been made to the database with select into, bulk copy, or parallel sort produces an error message instructing you to use dump database instead. (The writetext command does not have this protection.)

You do not have to set the select into/bulkcopy/pllsort option to true in order to select into a temporary table, since tempdb is never recovered. The option need not be set to true in order to run bcp on a table that has indexes, because tables with indexes are always copied with the slower version of bulk copy and are logged.

When single user is set to true, only one user at a time can access the database (single-user mode).

You cannot set single user to true in a user database from within a stored procedure or while users have the database open. You cannot set single user to true for tempdb.

The trunc log on chkpt option means that if the transaction log has more than 50 rows of committed transactions, the transaction log is truncated (the committed transactions are removed) every time the checkpoint checking process occurs (usually more than once per minute). When the Database Owner runs checkpoint manually, however, the log is not truncated. It may be useful to turn this option on while doing development work, to prevent the log from growing.

While the trunc log on chkpt option is on, dump transaction to a dump device is prohibited, since dumps from the truncated transaction log cannot be used to recover from a media failure. Issuing the dump transaction statement produces an error message instructing you to use dump database instead.

When the unique auto_identity index option is set to true, it adds an IDENTITY column with a unique, nonclustered index to new tables. By default, the IDENTITY column is a 10-digit numeric datatype, but you can change this default with the size of auto identity column configuration parameter. As with auto identity, the IDENTITY column is not visible when you select all columns with the select * statement. To retrieve it, you must explicitly mention the column name, SYB_IDENTITY_COL, in the select list.

If you need to use cursors or isolation level 0 reads with nonunique indexes, use the identity in nonunique index option.

Though you can set unique auto_identity index to true in tempdb, it is not recognized or used, and temporary tables created there do not automatically include an IDENTITY column with a unique index.

See the System Administration Guide for more information on database options.