I have a table "MYTABLE" which has an ID & NAME as its column, mapped JPA entity is similar with class "MyPersistence" with attributes id & name.
This table already has few records with unique ids as:
ID NAME
---------- ---------------
1254 DEV-SA12
234 DEV-SA345
Earlier the ids were generated manually but now I want to introduce table sequence generator, the sequence which I am using is named as "MY_GEN" and has current value as 100 (Restriction** - cannot change).
As you can see for Id 234 is already there, so when the sequence reaches at 233 and creates a new id, and tries to assign it, I am getting the following exception
Internal Exception: java.sql.SQLIntegrityConstraintViolationException:
ORA-00001: unique constraint (DEV.MYTABLE_ID_PK) violated
Any ideas how to avoid this ?
Thanks in advance
Related
I have a table 'client', which has 3 columns - id, siebel_id, phone_number.
PhoneNumber has a unique constraint. If I save a new client with an existing number, I'll get an error ERROR: duplicate key value violates unique constraint "phone_number_unique".
Is it possible to make PSQL or MyBatis showing 'siebel_id' of a record where the phone number already saved?
I mean to get a message like
'ERROR: duplicate key value violates unique constraint "phone_number_unique"
Detail: Key (phone_number)=(+79991234567) already exists on siebel_id...'
No, it's not possible to tweak the internal message that the PostgreSQL database engine returns accompannying an error. Well... unless you recompiled the whole PostgreSQL database from scratch, and I would assume this is off the table.
However, you can easily search for the offending row using SQL, as in:
select siebel_id from client where phone_number = '+79991234567';
I am using postgresql and sqlalchemy for my flask project.
I recently partitioned one of my big tables based on created_on using postgresql triggers.
But now if a try to insert a record into master table with db.session.add(obj) in sqlalchemy, i am getting error saying
Instance has a NULL identity key. If this is an auto-generated value, check that the database table allows generation of new primary key values, and that the mapped Column object is configured to expect these generated values. Ensure also that this flush() is not occurring at an inappropriate time, such as within a load() event.
Here I am using a sequence to increment my primary key. Please help me with this.
use autoincrement=True while defining your column example in my code sno is an autoincrement field :
class Contact(db.Model):
sno = db.Column(db.Integer, primary_key=True,autoincrement=True)
I just started using timescaleDB with postgresql. I have a database named storage_db which contains a table named day_ahead_prices.
After installing timescaledb, I was following Migrate from the same postgresql database to migrate my storage_db into a timescaledb.
When I did (indexes included):
CREATE TABLE tsdb_day_ahead_prices (LIKE day_ahead_prices INCLUDING DEFAULTS INCLUDING CONSTRAINTS INCLUDING INDEXES);
select create_hypertable('tsdb_day_ahead_prices', 'date_time');
It gave me the following error:
ERROR: cannot create a unique index without the column "date_time" (used in partitioning)
But when I did (indexed excluded):
CREATE TABLE tsdb_day_ahead_prices (LIKE day_ahead_prices INCLUDING DEFAULTS INCLUDING CONSTRAINTS EXCLUDING INDEXES);
select create_hypertable('tsdb_day_ahead_prices', 'date_time');
It was successful. Following which, I did
select create_hypertable('tsdb_day_ahead_prices', 'date_time');
and it gave me the following output:
create_hypertable
------------------------------------
(3,public,tsdb_day_ahead_prices,t)
(1 row)
I am a bit new to this so can anyone please explain to me what is the difference between both of them and why was I getting an error in the first case?
P.S.:
My day_ahead_prices looks as follows:
id | country_code | values | date_time
----+--------------+---------+----------------------------
1 | LU | 100.503 | 2020-04-11 14:04:30.461605
2 | LU | 100.503 | 2020-04-11 14:18:39.600574
3 | DE | 106.68 | 2020-04-11 15:59:10.223965
Edit 1:
I created the day_ahead_prices table in python using flask and flask_sqlalchemy and the code is:
class day_ahead_prices(db.Model):
__tablename__ = "day_ahead_prices"
id = db.Column(db.Integer, primary_key=True)
country_code = db.Column(avail_cc_enum, nullable=False)
values = db.Column(db.Float(precision=2), nullable=False)
date_time = db.Column(db.DateTime, default=datetime.now(tz=tz), nullable=False)
def __init__(self, country_code, values):
self.country_code = country_code
self.values = values
When executing CREATE TABLE tsdb_day_ahead_prices (LIKE day_ahead_prices INCLUDING DEFAULTS INCLUDING CONSTRAINTS INCLUDING INDEXES); you're telling the database to create the tsdb_day_ahead_prices table using the day_ahead_prices as a template (same columns, same types for those columns), but you're also telling it to include the default values, constraints and indexes that you have defined on the original table, and apply/create the same for your new table.
Then you are executing the timescaledb command that makes the tsdb_day_ahead_prices table
a hypertable. A hypertable is an abstraction that hides away the partitioning of the physical
table. (https://www.timescale.com/products/how-it-works). You are telling
TimescaleDB to make the tsdb_day_ahead_prices a hypertable using the date_time column as a partitioning key.
When creating hypertables, one constraing that TimescaleDB imposes is that the partitioning column (in your case 'date_time') must be included in any unique indexes (and Primary Keys) for that table. (https://docs.timescale.com/latest/using-timescaledb/schema-management#indexing-best-practices)
The first error you get cannot create a unique index without the column "date_time" is exactly because of this. You copied the primary key definition on the id column. So the primary key is preventing
the table to be a hypertable.
The second time, you created the tsdb_day_ahead_prices table but you didn't copy
the indexes from the original table, so the primary key is not defined (which is really a unique index). So the creation of the hypertable was successfull.
The output you get from the create_hypertable function tells you that you have a new hypertable, in the public schema, the name of the hypertable, and the internal id that timescaledb uses for it.
So now you can use the tsdb_day_ahead_prices as normal, and timescaledb underneath will make sure the data goes into the proper partitions/chunks
Does the id need to be unique for this table?
If you're going to be keeping time-series data
then each row may not really be unique for each id, but may be uniquely identified by the id at a given time.
You can create a separate table for the items that you're identifying
items(id PRIMARY KEY, country_code) and have the hypertable be
day_ahead_prices(time, value, item_id REFERENCES items(id))
I am migrating data from MSSQL.
I created the database in PostgreSQL via npgsql generated migration. I moved the data across and now when the code tries to insert a value I am getting
'duplicate key value violates unique constraint'
The npgsql tries to insert a column with Id 1..how ever the table already has Id over a thousand.
Npgsql.EntityFrameworkCore.PostgreSQL is 2.2.3 (latest)
In my context builder, I have
modelBuilder.ForNpgsqlUseIdentityColumns();
In which direction should I dig to resolve such an issue?
The code runs fine if the database is empty and doesn't have any imported data
Thank you
The values inserted during the migration contained the primary key value, so the sequence behind the column wasn't incremented and is kept at 1. A normal insert - without specifying the PK value - calls the sequence, get the 1, which already exists in the table.
To fix it, you can bump the sequence to the current max value.
SELECT setval(
pg_get_serial_sequence('myschema.mytable','mycolumn'),
max(mycolumn))
FROM myschema.mytable;
If you already know the sequence name, you can shorten it to
SELECT setval('my_sequence_name', max(mycolumn))
FROM myschema.mytable;
Hello
I have a main table BASECOMPANYDATA with BaseCompanyDataID as a PK. This is inhereted by
2 other tables CUSTOMERS & PRODUCTCOMPANIES. Now I have the table CONTACTS which I
want to connect with the 2 others as the customers and the productcompanies will have 0 or
more contacts. So I made a FK(BaseCompanyID) in CONTACTS and connected to the
BASECOMPANYDATA PK(BaseCompanyDataID). But when I am trying to insert a contact for
a record which exists in CUSTOMERS I get the following error:
ERROR: insert or update on table "xxxxx" violates foreign key contrain "xxxxx"
DETAIL: Key (BaseCompanyDataID)=(17) is not present in table "BaseCompanyData".
This ID exists in the above inherited table (BaseCompanyData).
Can someone explain why is this happening?
Thanks in advance
PS:Well, I have 4 tables:
1.BASECOMPANYDATA with BaseCompanyDataID as PK and some other fields.
2.CUSTOMERS which inherits from the above table so it has CustomerID as PK and has the fields of the BASECOMPANYDATA table namely BaseCompanyDataID etc.
3.PRODUCTCOMPANIES which inherits from BASECOMPANYDATA so it has the fields ProductCompanyID as PK and the fields of the inherited table like BaseCompanyDataID etc.
4.CONTACTS with ContactID as PK and BaseCompanyDataID as a FK. I tried to connect the table CONTACTS with 2 different ways. a. CONTACTS->BaseCompanyID with CUSTOMERS->BaseCompanyDataID and CONTACTS->BaseCompanyID with PRODUCTCOMPANIES->BaseCompanyDataID b. CONTACTS->BaseCompanyID with BASECOMPANYDATA->BaseCompanyDataID The result was the same error. Any answer on how I can create the FK using the inheritance, if there is. Thanks in advance
Did you read through the inheritance docs? Especially the 5.8.1. Caveats section?
http://www.postgresql.org/docs/9.0/static/ddl-inherit.html
...
Similarly, if we were to specify that cities.name REFERENCES some other table, this constraint would not automatically propagate to capitals. In this case you could work around it by manually adding the same REFERENCES constraint to capitals.
edit:
Inheritance is only half implemented in Postgsresql. If you want to save typing check out like in create table
In your first question I see the person recommended exactly the same thing I said. And now you have a problem? Hmm ...
This is pseudo sql I get from your repost:
base
baseid
customers(base)
baseid
id
products(base)
baseid
id
contacts
id
baseid references base(baseid)
Just do it the good old fashioned way!
base
id
customers
base_id references base(id)
id
products(base)
base_id references base(id)
id
contacts
id
base_id references base(id)