Questions tagged [sequence]

An object that can generate unique integers.

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82
votes
10answers
275k views

How do I use currval() in PostgreSQL to get the last inserted id?

I have a table: CREATE TABLE names (id serial, name varchar(20)) I want the "last inserted id" from that table, without using RETURNING id on insert. There seem to be a function CURRVAL(), but I don'...
36
votes
2answers
4k views

Why are Denali sequences supposed to perform better than identity columns?

In his answer to Which is better: identity columns or generated unique id values? mrdenny says: When SQL Denali comes out it will support sequences which will be more efficient than identity, but ...
25
votes
1answer
5k views

Sequence - NO CACHE vs CACHE 1

Is there any difference between a SEQUENCE declared using NO CACHE and one declared using CACHE 1 in SQL Server 2012+? Sequence #1: CREATE SEQUENCE dbo.MySeqCache1 AS INT START WITH 1 ...
23
votes
2answers
52k views

How to generate a sequence in mysql

Consider this table in mysql create table numbers (number int); insert into numbers values (3), (2), (9); select * from numbers; +--------+ | number | +--------+ | 3 | | 2 | | 9 | +---...
20
votes
1answer
27k views

PostgreSQL - Truncate a table on cascade and reset all hierarchic sequences with 1

Is there any way to reset all the sequences of tables, when truncate a table on cascade. I already read this post How to reset sequence in postgres and fill id column with new data? ALTER SEQUENCE ...
16
votes
1answer
85k views

Fixing table structure to avoid `Error: duplicate key value violates unique constraint`

I have a table which is created this way: -- -- Table: #__content -- CREATE TABLE "jos_content" ( "id" serial NOT NULL, "asset_id" bigint DEFAULT 0 NOT NULL, ... "xreference" varchar(50) ...
14
votes
2answers
33k views

Resetting a SQL Server 2012 sequence

I'm in the process of testing and populating a specific table that leverages the SEQUENCE object. In this process I'm testing populating the table with tens of thousands of insert lines (as I'm ...
13
votes
4answers
5k views

What can go wrong using the same sequence across multiple tables in postgres?

We are considering using a shared sequence to assign ids to primary keys for all of the tables in our database. There are about 100 of them. Only a couple are inserted to frequently and regularly. We ...
12
votes
1answer
29k views

Most efficient way to add a serial column to a huge table

What's the fastest way to add a BIGSERIAL column to a huge table (~3 Bil. rows, ~ 174Gb)? EDIT: I want the column to be incremented values for existing rows (NOT NULL). I didn't set a fillfactor (...
12
votes
1answer
5k views

Sequence is reusing

I have a sequence that generates tracking numbers for objects in my system. It had been working fine for quite some time. Last week we noticed that it was starting to re-use values. What seems to ...
11
votes
3answers
27k views

How do I create a table with a column that uses a sequence?

I have the following CREATE TABLE [MyTable] ( [ID] [bigint] PRIMARY KEY NOT NULL, [Title] [nvarchar](64) NOT NULL ) CREATE SEQUENCE MyTableID START WITH 1 INCREMENT BY 1 NO CACHE ...
11
votes
3answers
10k views

How could sequence.nextval be null in Oracle?

I have an Oracle sequence defined like so: CREATE SEQUENCE "DALLAS"."X_SEQ" MINVALUE 0 MAXVALUE 999999999999999999999999999 INCREMENT BY 1 START WITH 0 NOCACHE NOORDER NOCYCLE ; ...
10
votes
1answer
14k views

Explicitly granting permissions to update the sequence for a serial column necessary?

Recently I did create a table as a superuser including a serial id column, e.g., create table my_table ( id serial primary key, data integer ); As I wanted my non-superuser user to have ...
9
votes
1answer
3k views

Compacting a sequence in PostgreSQL

I have a id serial PRIMARY KEY column in a PostgreSQL table. Many ids are missing because I have deleted the corresponding row. Now I want to "compact" the table by restarting the sequence and ...
9
votes
1answer
3k views

How can I implement a sequence for each foreign key value?

In a PostgreSQL (9.3) database, I have a one-to-many relationship between Accounts and Customers, so within the Customers table, I have a globally-unique id for the primary key of each Customer, plus ...
8
votes
2answers
915 views

Does ordering by auto-incrementing PK ensure chronological order?

Is it safe to assume that ordering by an auto-incrementing PK in Postgres will order the records chronologically, from a creation standpoint? I have a many to many relationship, from which I don't ...
8
votes
3answers
51k views

How to get the next value of sequence?

Could somebody tell what is wrong with obvious query below: db2 => select next value for schema_name.sequence_name; As a result I'm getting: SQL0104N An unexpected token "END-OF-STATEMENT" ...
8
votes
2answers
10k views

postgres sequence problems, manually created pids, and proper sequence resetting

Developers encountered issues with sequences in our postgres 9.6 database over the past year, where they stop working, so they have resorted to things like inserting rows with a pid manually created ...
8
votes
2answers
3k views

SQL Server 2008: sequence which restarts daily

I have to add a trigger which should update a column using the following format strings: <current_date>_<per_day_incremental_id>, e.g 2015-10-01_36. Ids must be incremental and gaps are ...
7
votes
3answers
15k views

Using the same sequence twice in a PL/SQL statement

I wrote the snippet of PL/SQL today: declare first_id number; second_id number; begin insert into table (sort_nr, text_id, unit_id) values(..., table_seq.nextval, table_seq.nextval) returning ...
6
votes
3answers
4k views

Prevent explicit insert into serial columns

I want to prevent explicit inserts into serial columns. I have come up to the following trigger: drop table test_table; create table test_table( id bigserial primary key, foobar text ); create or ...
6
votes
1answer
1k views

Guarantee SQL Server Identity Columns that two consecutive values differ by constant increments?

I posed a question about Denali sequences here and another question about emulation of identity columns in Oracle Global Tables here. I always thought that I could trust that identity values ...
6
votes
2answers
11k views

Postgres: Get nextval in sequence without actually incrementing sequence?

It looks like select nextval('table_name') actually does the value increment. My goal is to "predict" the nextval value on all tables in the database without actually making any incrementation. This ...
6
votes
1answer
2k views

Postgresql behavior at end of sequence

As per subject when a sequence hits its max val what happens? What is the behavior? I have a big table with a sequence as a primary key and would like to know. Thanks.
6
votes
1answer
11k views

How to get the sequence name for a serial column

As far as I can tell, this query should show the expression for the new value of a serial column: select d.adsrc from ( SELECT a.attrelid, a.attnum, n.nspname, c.relname, a.attname FROM pg_catalog....
6
votes
1answer
21k views

The InnoDB log sequence number is in the future

Our site was getting intermittent database errors and I asked my webhost to check what's happening. After some inspection they found that the database has few issues and tried repairing it. Finally I ...
6
votes
2answers
3k views

How can I change the sequence_name parameter after renaming a sequence (PostgreSQL)

I have renamed a sequence with the following command: ALTER SEQUENCE TableIdSeq RENAME TO NewTableIdSeq; however, when I issue the \d NewTableIdSeq command, I get the following output: ...
5
votes
3answers
7k views

How to determine which tables use a sequence in SQL Server

I have a sequence in a SQL Server 2012 database that appears in sys.sequences. How do I determine which tables use this sequence? I do not have sufficient permissions to view the definition of this ...
5
votes
2answers
22k views

Adding a sequence number to existing rows

I have a table with an OrderSequence column. The schema looks roughly like this: id Name OrderSequence I have an array of ids ["1", "2", "3", "4"] from an application, and I want to set the ...
5
votes
2answers
10k views

Oracle ROWID, can we assume it is sequential in a insert-only scenario?

How safe is it to assume that ROWID is sequential or ascending when a table is only inserted to? and why? I had a situation where I had to verify whether new records were added to table which has no ...
5
votes
2answers
3k views

Alternative to sequence and timestamp: uniquely ordering records in time

Oracle 11gR2 Exadata I'm required to uniquely identify when records are created in time. Sequence caching means I cannot use a sequence-based ID and batching inserts means that all records inserted ...
5
votes
1answer
21k views

INSERT INTO table FROM SELECT * with nextval() specification

I need to copy records within the same table changing only one field. My table has default-generated sequence entry_id_seq, however I am not sure id column is SERIAL (how to check that?). \d tab ...
5
votes
3answers
6k views

Reset a sequence every year

Every time a new row is added to the table below, I want the sequence (Import Permit No) to be increased by 1....20160001, 20160002, etc and reset to 20170001, 20170002, etc in a new year. CREATE ...
4
votes
3answers
463 views

Achieving "sequence number", rather than dateTime, for updates; postgres specifically

So a postgres database (specifically, an AmazonRDS instance fwiw). It's easy enough to arrange things to get the last updated (or created) time for any record. That information would be a datetime. ...
4
votes
3answers
858 views

Is there a good way to link tables and sequences?

I'm pretty sure you can't do this like you can with foreign keys but I'd like to document at the database level (even if it's just as a bit of free text somewhere) these relationships. Is there some ...
4
votes
3answers
5k views

Copy table with separate sequences for serial columns

While creating a column management tool I came across the need to quickly replicate tables in PostgreSQL so I would not test new tools with non-test tables. To effectively test the new column tool ...
4
votes
1answer
371 views

How to safely replace the old table with its cleaned copy?

I have created a table_cleaned like table and inserted unique values from table into table_cleaned. Now I want to replace table with table_cleaned with DROP TABLE table; ALTER TABLE table_cleaned ...
4
votes
1answer
9k views

Permission for sequence in another schema

Postgres 9.3 Debian 7.0 I created a specific schema for a specific user and created a view in this schema for this user, so it's the only table he knows that exists. The problem is that this same ...
4
votes
1answer
2k views

Is it possible to re-initialize sequence

How do I re-initialize the sequence value without drop and recreating them again For example, the current sequence value is 3, now I want to restart it with 1 again.
4
votes
2answers
783 views

How can I safely rename a sequence in PostgreSQL, ideally without downtime?

We want to rename some sequences in our production database for certain reasons. Is there a way to do this safely in production without having to first close all connections to the database? It's ...
4
votes
1answer
2k views

CREATE SEQUENCE using expressions with psql variables for parameters

I've been playing with Postgres for a week or so and I'm seeing if it's possible to set the min/max values for a sequence using an expression. The specific goal is to automate create-scripts for ...
4
votes
2answers
12k views

Reset every Oracle sequence to the MAX value of its target table PK?

I finally got around to migrating from MySQL to Oracle and was pleasantly surprised just how well of a job the SQLDeveloper Migration tool did. It even took my AUTOINCREMENT fields and created ...
4
votes
1answer
1k views

Postgresql import from SQL Server - how to auto-generate sequences

As the title states I'm switching from SQL Server to Postgresql via SQL dump. The tables and views have been migrated correctly, alas the IDENTITY columns have not been properly converted into ...
4
votes
1answer
71 views

Sequence object blocking

We have been experiencing an issue with a sequence object we have that is called a lot. It is used to assign a value prior to a record being inserted into a table. Today I saw that 700+ sessions (all ...
3
votes
4answers
559 views

What free database software support sequences [closed]

I have a requirement that a database must support sequences. I know oracle and PostgreSQL support it. Are there any other free database software that support database sequences? it would be great if ...
3
votes
1answer
3k views

How can I create a gapless sequence?

Observation: I have a serial index on a table in a PostgreSQL instance, and I execute a function that inserts a new record into that table. The function fails (reason not important), and the ...
3
votes
3answers
3k views

Create unique sequence per set of rows sharing the same foreign key value

In my system, I want each user to have an own id sequence for his articles. So, I have created a database that has a table that depicts a correspondence between users and their articles. Here is the ...
3
votes
1answer
6k views

PostgreSQL SELECT primary key as "serial" or "bigserial"

I've meshed together a way to determine what the data_type is as in the data_type you use in the syntax when creating a new table based off of the PostgreSQL wiki page. If there is something wrong ...
3
votes
1answer
1k views

Oracle sequence generation performance during persists of large data sets

In the context of an Oracle sequence, when persisting > 200 million records, is there a performance hit on the database if the sequence cache is the default value of 10000? That is to say does ...
3
votes
1answer
3k views

Postgres, how insert "0" value into serial?

I have a serial id in my application table. However, I would like to insert a single 0 id record to mean global. Is there a way I can insert this into my table without affecting the counter?