sprintf(buf," :restypmod %d ",node->restypmod);

appendStringInfo(str,buf);

appendStringInfo(str," :resname ");

if (*node->resname)

sprintf(buf,"\"%s\"",node->resname);/* fix for SELECT col AS "my name" */

buf[0]='\0';

sprintf(buf,"\"%s\"",node->resname);/* fix for SELECT col AS "my name" */

appendStringInfo(str,buf);

sprintf(buf," :reskey %d ",node->reskey);

appendStringInfo(str,buf);

appendStringInfo(str,buf);

}

}

}

{

local_node->resname= (char*)palloc(length+1);

StrNCpy(local_node->resname,token,length+1);

StrNCpy(local_node->resname,token+1,length+1-2);/* strip quotes */

}

token=lsptok(NULL,&length);/* eat :reskey */

create sequence - create a new sequence number generator

.BR"Create sequence"

will enter a new sequence number generator into the current data base.

Actually, new single block

Actually,anew single-record

.BR table

with name

.IR seqname

\*(lqowned\*(rq by the user issuing the command.

.PP

The

.BR"increment"

is optional clause. Positivevalue will make ascending sequence,

.BR increment

clauseis optional. A positivevalue will make an ascending sequence,

negative - descending. Default value is 1.

.PP

The optional integer

.BR minvalue

determines the minimum valuea sequence canbe. Defaults are

determines the minimum valuethe sequence cangenerate. Defaults are

1/-2147483647 for ascending/descending sequences.

.PP

Use optional integer

The optional integer

.BR maxvalue

to determinethe maximum valuefor sequence. Defaults are

determinesthe maximum valuethe sequence can generate. Defaults are

2147483647/-1 for ascending/descending sequences.

.PP

Theoptinal

.BR"start"

valueenables sequencetobegin anywhere. Default is

Theoptional

.BR start

valuesets the first valuetobe generated. Default is

.BR minvalue

for ascending sequences and

.BR maxvalue

.BR cache

option enables sequence numbers to be preallocated and

stored in memory for faster access. The minimum value is 1

(i.e. - no cache) and it is default.

.BR NOTE:

each backend uses own cache to store allocated numbers.

Cached but not used in current session numbers will be lost.

(one value will be allocated at a time, i.e., no cache)

and that is the default. See below for details.

.PP

The optional

.BR cycle

keyword may be used to enable sequence to continuewhen the

keyword may be used to enablethesequence to continueafter the

.BR maxvalue/minvalue

has been reached by ascending/descending sequence.

If the limit is reached, the next number generated will be

whatever the

.BR minvalue/maxvalue

is.

.PP

After sequence created,You may use function

Afterasequenceobject has beencreated,you may use the function

.BR nextval

with sequence name as argument to get new number from sequence

specified.

Function

with the sequence name as argument to generate a new number from the

specified sequence.

.PP

The function

.BR currval

('sequence_name')

may be used todeterminenumber returned by last call to

may be used tore-fetch thenumber returned by the last call to

.BR nextval

for specified sequence in current session.

for the specified sequence in the current session.

.BR NOTE:

currval will return an error if nextval has never been called for the

given sequence in the current backend session. Also beware that it

does not give the last number ever allocated, only the last one allocated

by this backend.

.PP

Use a query like

.nf

Use query like

select * from <sequence_name>;

to get parameters of a sequence.

SELECT * FROM <sequence_name>;

.fi

to get the parameters of a sequence. Aside from fetching the original

parameters, you can use

.nf

SELECT last_value FROM <sequence_name>;

.fi

to obtain the last value allocated by any backend.

.PP

Low-level locking is used to enable multiple simultaneous calls

to a generator.

Low-level locking is used to ensure that multiple backends can safely use

a sequence object concurrently.

.PP

.BR NOTE:

Unexpected results may be obtained if a cache setting greater than one

is used for a sequence object that will be used concurrently by multiple

backends. Each backend will allocate "cache" successive sequence values

during one access to the sequence object and increase the sequence

object's last_value accordingly. Then, the next cache-1 uses of nextval

within that backend simply return the preallocated values without touching

the shared object. So, numbers allocated but not used in the current session

will be lost. Furthermore, although multiple backends are guaranteed to

allocate distinct sequence values, the values may be generated out of

sequence when all the backends are considered. (For example, with a cache

setting of 10, backend A might reserve values 1..10 and return nextval=1, then

backend B might reserve values 11..20 and return nextval=11 before backend

A has generated nextval=2.) Thus, with a cache setting of one it is safe

to assume that nextval values are generated sequentially; with a cache

setting greater than one you should only assume that the nextval values

are all distinct, not that they are generated purely sequentially.

Also, last_value will reflect the latest value reserved by any backend,

whether or not it has yet been returned by nextval.

.PP

.nf