I am using oracle_fdw 2.2.0devel, PostgreSQL 10.13, Oracle client 18.3.0.0.0
We have a foreign table in Postgres defined as this:
CREATE FOREIGN TABLE public.tickers
(
ticker_id INTEGER,
ticker VARCHAR,
)
SERVER oracle
OPTIONS (table 'TICKERS', schema 'COMMENTARY', readonly 'true');
This is connecting to as 12c SE database. This works fine, however, I've noticed that the query in Oracle is actually looking like this:
SELECT
/*618157932326e692807010156f98ddac*/
r2."TICKER_ID",
r2."TICKER"
FROM "COMMENTARY"."TICKERS" r2
WHERE (upper(r2."TICKER") = upper(:p1))
Why would it automatically be adding the "UPPER" clause? This slows the Oracle query and does not use an index, unless I create a FBI using "upper".
Was wondering if there was some option I'm supposed to disable.......
The only way that oracle_fdw will generate an Oracle query that uses the upper function is if the original PostgreSQL query already had upper in it.
Related
I can use the pg_indexes view to get the SQL used to create an index (as in the sql in this question: How to get indexes, primary keys, and all constraints for a schema in PostgreSQL using standard sql).
Is there a way to get the SQL for constraints in PostgreSQL? I'm not seeing a pg_constraints table and the information I'm finding on line isn't pointing me to a solution, for example, these are some of the hits coming up when I Google the terms (postgresql get sql for constraint).
https://dba.stackexchange.com/questions/206562/postgres-read-constraints-definition
Postgres Check Constraint definition
https://www.geeksforgeeks.org/sql-query-to-display-all-the-existing-constraints-on-a-table/
I'm trying to migrate my sqlite database to postgresql.
I'm new to postgresql but stuck on this simple issue.
I fist used the pgloader tool to migrate to postgresql and have a working database. I see it created the table this way:
CREATE TABLE "AOrder"
(
"OrderNumber" bigserial NOT NULL,
"BuyerName" text,
etc
)
WITH (
OIDS=FALSE
);
ALTER TABLE "AOrder"
OWNER TO postgres;
Using pgadmin3 if I run the SQL query:
select
*
from AOrder
This returns the column names plus all the data as expected.
However, the following:
select
*
from "AOrder"
This returns just the column names and no data. Where's the data?
So it's not a problem with capitalization. Is there a setting in postgresql that is making this happen?
(This is ultimately the root problem for me since I am then using Sqlachemy which inserts the double quotes in queries. I could not figure out a way to change that behavior.)
Thanks!
I know that dblink can be queried directly like:
select * from dblink('kenyon_dblink','select * from test') as t1 (id integer,name varchar);
I wonder if I can query foreign servers without creating foreign tables, since my query strings are generated dynamically.
Yes you can, just open a dblink connection in the same session with dblink_connect() (named or unnamed).
Example:
Is there any shortcut for using dblink in Postgres?
Example with dynamic SQL:
Syntax error in function using dblink to replicate new data
This works for connections between PostgreSQL DBs, not for other RDBMS. Per documentation:
dblink is a module that supports connections to other PostgreSQL
databases.
We are SQL Server users and recently we have one database on PostgreSQL. For consistency purpose we are replication database on SQL Server 2000 to other database on SQL Server 2000 and now we would also need to replicate it to the database on PostgreSQL. We were able to do that using ODBC and Linked Server. We created an ODBC DSN for database on PostgreSQL and using that DSN we created a Linked Server on SQL Server. We were able to replicate tables from SQL Server database to that linked server and hence to PostgreSQL database successfully. Now the issue faced is while replication, the datatype bit, numeric(12,2) and decimal(12,2) are converted to character(1), character(40) and character(40) respectively. Is there any solution on how to retain those data types in PostgreSQL database ? I mean the bit should become boolean, and numeric and decimal data type should remain as it is in the replicated table of postgresql. We are using PostgreSQL 9.x
SQL Server table,
CREATE TABLE tmtbl
(
id int IDENTITY (1, 1) NOT NULL PRIMARY KEY,
Code varchar(15),
booleancol bit,
numericcol numeric(10, 2),
decimalcol decimal(10, 2)
)
after being replicated to PostgreSQL it becomes,
CREATE TABLE tmtbl
(
id integer,
"Code" character varying(15),
booleancol character(1),
numericcol character(40),
decimalcol character(40),
)
Thank you very much.
Please, use:
boolean type for true/false type of columns (there's no bit type in postgres);
NUMERIC type exists also in the PostgreSQL (according to the SQL standard). But I suggest you should better use real PostgreSQL type, as it will be working faster.
I recommend you to create target table on the PostgreSQL side manually, specifying proper field types, as ODBC+Linked Server combination is not doing it's job properly.
You can always consult this part of the official documentation for existing data types.
have you heard of Foreign Data Wrappers?
http://wiki.postgresql.org/wiki/Foreign_data_wrappers
I am new to PostgreSQL. I have 2 databases in PostgreSQL 9.0, db1 and db2, and with db2 I have read only access. I want to create a stored function that would be otherwise easily accomplished with a JOIN or a nested query, something PostgreSQL can't do across databases.
In db1, I have table1 where I can query for a set of foreign keys keys that I can use to search for records in a table2 in db2, something like:
SELECT * from db2.table2 WHERE db2.table2.primary_key IN (
SELECT db1.table1.foreign_key FROM db1.table1 WHERE
db1.table1.primary_key="whatever");
What is the best practice for doing this in Postgres? I can't use a temporary tables in db2, and passing in the foreign keys as a parameter in a stored function running in db2 doesn't seem like a good solution.
Note: the keys are all VARCHAR(11)
You'll want to look into the db_link contrib.
As an aside if you're familiar with C, there also is a cute functionality called foreign data wrappers. It allows to manipulate pretty much any source using plain SQL. Example with Twitter:
SELECT from_user, created_at, text FROM twitter WHERE q = '#postgresql';