I am trying to drop a foreign key in DB2 through the command line. I have succeeded in this many times and I am sure that I am using the correct syntax:
db2 "alter table TABLENAME drop constraint fk_keyname"
Output:
DB21034E The command was processed as an SQL statement because it was not a
valid Command Line Processor command. During SQL processing it returned:
SQL0204N "FK_KEYNAME" is an undefined name. SQLSTATE=42704
All my foreign keys are created with an uppercase name. Except for the key I now want to drop. I don't know how to got created with a lowercase name but it seems that it will not drop keys that are lowercase.
When I try to add this foreign key (while it still exists) I get the following message:
DB21034E The command was processed as an SQL statement because it was not a
valid Command Line Processor command. During SQL processing it returned:
SQL0601N The name of the object to be created is identical to the existing
name "fk_keyname" of type "FOREIGN KEY". SQLSTATE=42710
Does anyone know how to drop foreign keys that have a lowercase name?
The answer by mustaccio worked. Tried all kinds of quotes but this way did the trick:
db2 'alter table TABLENAME drop constraint "fk_keyname"'
DB2 will convert object names to uppercase, unless they are quoted. Generally it's not a very good idea to create objects with lower- or mixed-case names. If your foreign key is actually "fk_keyname" (all lowercase), run db2 "alter table TABLENAME drop constraint \"fk_keyname\"" or db2 'alter table TABLENAME drop constraint "fk_keyname"'
This behaviour is not unique to DB2, by the way.
Related
I am trying to create an ID charfield column and set it as primary key to an existing table. So because it is an existing table when i generate Migrations django asks me to provide a default value. What can i enter as primary key default for existing rows? If i enter a single string e.x 'abcd' i will get error for existing rows on migrate because of duplicate value
Apologies.
I didn't read correctly.
I am new to the python language and django. I need to connect the django to the oracle database 11g, I have imported the cx_oracle library and using the instant client for connecting oracle with django, but when i run the command manage inspectdb > models.py. I get error as Invalid column identifier in the models.py. How could i solve it. I have only 2 tables in that schema i am connecting?
"Invalid column" suggests that you specified column name that doesn't exist in any of those tables, or you misspelled its name.
For example:
SQL> desc dept
Name
-----------------------------------------
DEPTNO
DNAME
LOC
SQL> select ndame from dept; --> misspelled column name
select ndame from dept
*
ERROR at line 1:
ORA-00904: "NDAME": invalid identifier
SQL> select imaginary_column from dept; --> non-existent column name
select imaginary_column from dept
*
ERROR at line 1:
ORA-00904: "IMAGINARY_COLUMN": invalid identifier
SQL>
Also, pay attention to letter case, especially if you created tables/columns using mixed case and enclosed those names into double quotes (if so, I'd suggest you to drop tables and recreate them, without double quotes. If you can't do that, you'll have to reference them using double quotes and exactly the same letter case).
So - check column names and compare them to your query. If you still can't make it work, post some more information - table description and your code.
I've faced the same problem. The problem is that Django expects your table have primary key (ID), so when your table is without key, it returns Invalid columns identifier.
https://docs.djangoproject.com/en/2.1/topics/db/models/#automatic-primary-key-fields
Problem.
After successful data migration from csv files to django /Postgres application .
When I try to add a new record via the application interface getting - duplicate key value violates unique constraint.(Since i had id's in my csv files -i use them as keys )
Basically the app try to generate id's that already migrated.
After each attempt ID increments by one so if I have 160 record I have to get this error 160 times and then when I try 160 times the time 161 record saves ok.
Any ideas how to solve it?
PostgreSQL doesn't have an actual AUTO_INCREMENT column, at least not in the way that MySQL does. Instead it has a special SERIAL. This creates a four-byte INT column and attaches a trigger to it. Behind the scenes, if PostgreSQL sees that there is no value in that ID column, it checks the value of a sequence created when that column was created.
You can see this by:
SELECT
TABLE_NAME, COLUMN_NAME, COLUMN_DEFAULT
FROM
INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_NAME='<your-table>' AND COLUMN_NAME = '<your-id-column>';
You should see something like:
table_name | column_name | column_default
--------------+---------------------------+-------------------------------------
<your-table> | <your-id-column> | nextval('<table-name>_<your-id-column>_seq'::regclass)
(1 row)
To resolve your particular issue, you're going to need to reset the value of the sequence (named <table-name>_<your-id-column>_seq) to reflect the current index.
ALTER SEQUENCE your_name_your_id_column_seq RESTART WITH 161;
Credit where credit is due.
Sequence syntax is here.
Finding the name is here.
I am running into this error when i migrate.Is there any way to save data on my database.I know that dropping the auth_user table will fix the issue. I am running postgresql.
Thanks!
FATAL ERROR - The following SQL query failed: ALTER TABLE "api_poi" ADD CONSTRAINT "user_id_refs_id_20f256ff" FOREIGN KEY ("user_id") REFERENCES "auth_user" ("id") DEFERRABLE INITIALLY DEFERRED;
The error was: insert or update on table "api_poi" violates foreign key constraint "user_id_refs_id_20f256ff"
DETAIL: Key (user_id)=(1) is not present in table "auth_user".
There is a row in api_poi which has user_id set to 1, but there is no row in auth_user which has id set to 1.
So it is impossible to define a foreign key constraint like you are trying to do.
You will have to add rows to auth_user or remove rows from api_poi until the foreign key constraint is satisfied.
Include 'django.contrib.admin', in your INSTALLED_APP, then run migrations and migrate again.
I too had the very hardship. However, I had to flush all the data recorded in the database to avert this error as I didn't find any of the solutions given above helpful.
$ python manage.py flush
And confirmed yes.
I certainly would not recommend this way of bypassing integrity error if you care about the existing data in your DB coz it will nullify the table by omitting all the data outta the table.
go to the database and insert code
ALTER SEQUENCE TableName_id_seq RESTART WITH 'last id number';
for example :
ALTER SEQUENCE account_id_seq RESTART WITH 100;
I trying to code a many to many relationship in c++ sqlite3.
in the diagram below,
managers can add many job opportunities.
jobs opportunities is being add by many managers
my create table statements
"CREATE TABLE Manager(" \
"manager_id INTEGER PRIMARY KEY NOT NULL,"\
"name varchar(45) NOT NULL);"
"CREATE TABLE jobs ("
"jobId INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"\
"jobTitle varchar(45) NOT NULL);"
"CREATE TABLE Add ("
"manager_id,jobId INTEGER PRIMARY KEY NOT NULL,"\
"date varchar(45) NOT NULL,"\
"FOREIGN KEY(manager_id) REFERENCES Manager(manager_id),"\
"FOREIGN KEY(job_id) REFERENCES jobs(job_id));";
my manager table is populated with the following information
1|john
2|bob
let's say manager john has added two jobs,jobTitle jobA and jobB
then my insert statement code will look like this.http://pastebin.com/0E8CzPgX
then my jobs tables is populated with the following information
1|jobA
2|jobB
the final step is to take the id of john(manager id = 1) and the two jobsId(1,2) and add it inside
the add table. I don't have an idea of how should I code
so that the add table will become like this.
add table
manager_id|job_id|date
1 | 1 |30-01-2014
1 | 2 |30-01-2014
please advise.thanks
Do you mean something like
sql = "INSERT INTO Add(manager_id,jobId,date) VALUES (?,?,?);";
?
Your problem seems to be that you defined jobID to be the primary key of the table Add, which you don't need.
jobId INTEGER PRIMARY KEY NOT NUL
A common approach to many-to-many relations in a database is to include an intermediate table.
This intermediate table (let's call it Manager_jobs) would have at least 2 columns, both referring to other tables via foreign key. The first attribute would be the primary key of Manager, the second one the primary key of jobs.
Each time you add a job, you just add an entry to Manager_jobs with the foreign keys respectively.
So, Manager_jobs would look like this:
ManagerID | JobID
==========|======
4 | 2
3 | 2
4 | 1
As you can see, Manager_jobs can encode that a Manager has multiple jobs assigned and vice versa.
This approach, of course, requires you to have some form of primary key for both data tables.