Let say I have a schema world and a table city in a Postgres DB.
I can set a comment on the table (or view, function, index, ...) with the command below:
COMMENT ON TABLE world.city IS 'This is a test comment';
How can I see this comment in CLI (Not GUI)?
I tried using show command thinking it might help, but got a syntax error!
SHOW TABLE world.city;
ERROR: syntax error at or near "table"
LINE 1: show table world.city;
The same happened with show command on views!
\d+ world.city
From the documentation:
The command form \d+ is identical, except that more information is displayed: any comments associated with the columns of the table are shown, as is the presence of OIDs in the table, the view definition if the relation is a view, a non-default replica identity setting and the access method name if the relation has an access method.
Related
I have to write a sql script to modify a lot of types of columns in my db2 database.
Everything goes well excpet for one specific table (script used is the same as others tables) and db2 returns always an error I don't understand.
Here is my script :
ALTER TABLE "TEST"."CLIENT"
ALTER COLUMN C_CODE
SET DATA TYPE CHAR(16 OCTETS);
and the error :
SQL Error [42997]: Function not supported (Reason code = "21")..
SQLCODE=-270, SQLSTATE=42997, DRIVER=4.26.14
I try to modify some others columns on the same table, but I always receive the same error.
Do you, by any chance, have an idea?
Thanks in advance
The error SQL0270N (sqlcode = -270) has many possible causes, and the specific cause is indicated by the "reason code".
In this case the "reason code 21" means:
A column cannot be dropped or have its length, data type, security,
nullability, or hidden attribute altered on a table that is a base
table for a materialized query table.
The documentation for this sqlcode on Db2-LUW is at:
https://www.ibm.com/docs/en/db2/11.5?topic=messages-sql0250-sql0499#sql0270n
Search for SQL0270N on that page, and notice the suggested user response:
To drop or alter a column in a table that is a base table for a materialized query table, perform the following steps:
1. Drop the dependent materialized query table.
2. Drop the column of the base table, or alter the length, data type, nullability, or hidden attribute of this column.
3. Re-create the materialized query table.
I first created a table, then I altered it. Just after alter command I am trying to view the tables by writing
show tables
command but it displays the error-
show is not valid at this position, expecting ADD, algorithm , ALTER,
Auto increment.......
I know this sounds like an "opinion" question, but I don't think it is.
Normally, I would consider not using "user" as a table name as it is a reserved word, and I would rather not bother having to deal with it when I write native SQL queries.
But I am not writing native SQL queries, but am having Symfony and the Doctrine ORM perform all the queries. And when I execute php bin/console make:user, Symfony prompts me to select the class name User which results with user as the table name. Furthermore, most of the tutorials I have read also use the name user. If using the name user is what is most common for other developers, I would rather stay consistent.
Most of the time, I don't have any issues, but every now and then, Doctrine crashes because it is querying the Postgres internal user table and not public.user. As a workaround, I tried adding * #ORM\Table(schema="public") to the User entity, but then when making migrations, it tries to duplicate the record resulting in errors. Maybe Symfony/Doctrine needs to be configured somewhere as using the public schema?
Thanks
Since my question was "Should the table name “user” be used in a Symfony project?", the following doesn't answer the question, but I am still posting it should it be helpful for others. Perhaps I will change the title to "How to use the table name “user” in a Doctrine project?", but not sure whether doing so is kosher.
I've since discovered other's experiencing issues resulting from this topic:
https://github.com/doctrine/dbal/issues/1222
https://github.com/symfony/maker-bundle/pull/545
Also found the following at doctrine-adding-mapping:
Be careful not to use reserved SQL keywords as your table or column
names (e.g. GROUP or USER). See Doctrine’s Reserved SQL keywords
documentation for details on how to escape these. Or, change the table
name with #ORM\Table(name="groups") above the class or configure the
column name with the name="group_name" option.
Which directed me to quoting-reserved-words which directed me to escape the name using ticks.
* #ORM\Table(name="`user`")
There is no table user in PostgreSQL.
Tutorials that use user as a table name are not trustworthy. However, if you consistently use double quotes, there should be no problem. Since you claim to have problems with native queries, you might have forgotten that occasionally.
One possible source of confusion is that there is a function named user in PostgreSQL. So if you use user in a context where a function is possible, you'll get a function call. If you use it with schema qualification, you will get an error that there is no such object. Otherwise, you will get a syntax error:
test=> SELECT user;
user
---------
laurenz
(1 row)
test=> SELECT * FROM user;
user
---------
laurenz
(1 row)
test=> TABLE user;
ERROR: syntax error at or near "user"
LINE 1: TABLE user;
^
test=> SELECT * FROM public.user;
ERROR: relation "public.user" does not exist
LINE 1: SELECT * FROM public.user;
^
I'm using CRecordset to query one table, but I use a second table to filter data. If in my GetDefaultSQL override method I return a table list with more than one table then I get this ERROR: column reference "ctid" is ambiguous. I know what a "ctid" column is, but I don't use it in my code. It's inserted into the original SQL statement by ODBC driver. How to fix this? How to tell the ODBC driver not to insert the "ctid" column?
I tried to call CRecordset::Open with readOnly parameter, as I assume that ODBC needs ctid to update the row, and I don't need to update them. But the error remains.
Also tried to add a primary key to the second table that was missing it, thinking if a table has a primary key then ODBC can use that instead of 'ctid', but again no luck. Makes sense though, because I don't fetch any column of that second table, and the second table is used just for filtering.
If I make a DB view to work around the issue, I get ERROR: column "ctid" does not exist.
You have to call CRecordset::Open with two parameters changed:
m_pSet->Open(CRecordset::snapshot, NULL, CRecordset::readOnly);
Then you can fetch both the joined tables and the view without errors. No "ctid" then.
I have an issue with psql. I am trying to select the records from a table but psql acts like the table doesnt exist. I have tried finding it and found that it resides in the 'public' schema. I have tried selecting from this table like so:
highways=# SELECT * FROM public.CLUSTER_128000M;
This does not work stating the following:
ERROR: relation 'public.CLUSTER_128000M' does not exist
I know that it definetly exists and that it is definetly in the 'public' schema so how can I perform a select statement on it?
Edit:
This was caused by useing FME to create my tables. As a result FME used " marks on the table names making them case sensitive. To reverse this see the comments below.
This issue was caused by the third party software FME using quotes around the names of the tables at time of creation. The solution to make the tables useable again was to use the following command:
ALTER TABLE "SOME_NAME" RENAME TO some_name