I need to migrate from Oracle to Postgres.
In Oracle I have .sql files calling nested .sql files (with input and output parameters each one) in this way: nested sql scripts and variables
Looking for a similar solution in Postgres I found this:
How to run postgres sql script from another script?
But what happens with the solution: \i other_script.sql
Can I pass input parameters to it? (and if yes, how?) Can I return parameters from it? (and if yes, how?)
Or the other_script.sql and the calling.script share variables?
Or there isn't an equivalent solution for input/output parameters. And variables are not shared between the two .sql files?
psql session variables are session based, so you can set any psql variable inside script, and you can read this variable outside script.
\set myvar some value
select :'myvar';
You can read more in psql documentation.
Related
I have successfully used &&1, &&2, &&3, etc. in my SQLPlus query, and was wondering if it is possible to use this with any Oracle query, not just through SQLPlus?
What are these "variables" properly called?
These are called, Substitution Variables. They are only for sqlplus. See reference documentation If you are referring to "other queries" such as withing PL/SQL, those use bind parameters.
3GLs provide mechanisms to prepare statements before executing them. E.g.
SELECT name
FROM people
WHERE age=:AGE
The same query can then be executed for different ages. But can such a statement also be prepared in a "plain" Oracle SQL client? Can the same be done in e.g. SQL Plus or dbForge Studio for Oracle as in Java or C# or any other programming language that supports prepared statements?
In dbForge Studio for Oracle, named parameters can be used, preceded by a colon :
SELECT *
FROM people
WHERE name=:name
The parameters can then be filled in with the "Edit parameters dialog box", available from the SQL toolbar.
I know you didn't ask about PostgreSQL but about Oracle. However, of note, PostgreSQL has this feature right in its SQL language.
The SQL standard includes a PREPARE statement, but it is only for use in embedded SQL. The PostgreSQL version of the PREPARE statement works like this:
PREPARE nameByAge(number) AS
SELECT name
FROM People
WHERE age=$1;
and you use it like this:
EXECUTE nameByAge(18);
EXECUTE nameByAge(50);
So unfortunately for Oracle SQLPlus the answer seems to be no, not bind variables. But SQLPlus has substitution variables, similar to shell scripts. You use them as &1, &2, &3, ... and they get their parameters from the way you call the SQLPlus script.
sqlplus user/password #script.sql 18
sqlplus user/password #script.sql 50
with the script.sql being
SELECT name
FROM People
WHERE age=&1;
this would work, even though it is not bind. But then, do you really care about the slight savings in repeat parse time? In fact Oracle hashes SQL statements and already replaces constants with bind variables to be able to better reuse query plans. So the savings you would get with PREPARE and BIND are really minuscule.
I have the following problem, I need to put in a script that is going to run before the new version is rolled the SQL code that enables the pgAgent in PostgreSQL. However, this code should be run on the maintenance database (postgres) and the database where we run the script file is another one.
I remember that in SQL Server there is a command "use " so you could do something like:
use foo
-- some code
use bar
-- more code
is there something similar in PostgreSQL?
You can put in your file something like:
\c first_db_name
select * from t; --- your sql
\c second_db_name
select * from t; --- your sql
...
Are you piping these commands through the psql command? If so, \c databasename is what you want.
psql documentation
You can't switch databases in Postgres in this way. You actually have to reconnect to the other database.
PostgreSQL doesn't have the USE command. You would most likely use psql with the --dbname option to accomplish this, --dbname takes the database name as a parameter. See this link for details on the other options you can pass in you will also want to check out the --file option as well. http://www.postgresql.org/docs/9.0/interactive/app-psql.html
well after looking on the web for some time I found this which was what I need it
http://www.postgresonline.com/journal/archives/44-Using-DbLink-to-access-other-PostgreSQL-Databases-and-Servers.html
I would like to run some ad hoc select statements in the IBM System I Navigator tool for DB2 using a variable that I declare.
For example, in the SQL Server world I would easily do this in the SQL Server Management Studio query window like so:
DECLARE #VariableName varchar(50);
SET #VariableName = 'blah blah';
select * from TableName where Column = #VariableName;
How can I do something similar in the IBM System I Navigator tool?
I ran across this post while searching for the same question. My coworker provided the answer. It is indeed possible to declare variables in an ad hoc SQL statement in Navigator. This is how it is done:
CREATE OR REPLACE VARIABLE variableName VARCHAR(50);
SET variableName = 'blah';
SELECT * FROM table WHERE column = variableName;
DROP VARIABLE variableName;
If you don't drop the variable name it will hang around until who knows when...
At the moment, we're working on the same issue at work. Unfortunaly, we concluded that this is not possible. I agree, it would be great but it just doesn't work that way. iNavigator doesn't support SET or Define. You can do that in embedded SQL but this is not embedded SQL. Even if you create a separate document (xxx.sql), then need to open this document to run the script what makes it an interactive script (that is, DECLARE SECTION is not allowed).
As an alternative, in the SQL screen/script you can use CL:. Anything after this prefix is executed as CL command. You may manipulate your tables (e.g. RNMF) this way.
As a second alternative, the iSeries does support Rexx scripts (default installed with the os). Rexx is good dynamic script language and it does support embedded SQL. I've done that a lot of times and it works great. I even created scripts for our production environment.
Just create one 'default' script with an example PREPARE and CURSOR statement and copy at will. With that script you can play around. See the Rexx manual for the correct syntax of exec-sql. Also, you do have STDIN and STDOUT but you can use 'OVRDBF' to point to a database table (physical file). Just let me know if you need an example Rexx script.
Notice that the manual "SQL embedded programming" does have Rexx examples.
Here are a couple of other alternatives.
Data Transfer Tool - You can run the iSeries Data Transfer Tool from the command line (RTOPCB). First, run the GUI version and create a definition file. If you edit this file with a text editor, you will see that this is just an old-fashioned INI file and you can easily find the line with the query in it. From there, you could write a batch file or otherwise pre-process the text file to allow you to manipulate the query before submitting it to the query tool.
QSHELL - If you can log on to the iSeries interactively, then you may find the QSHELL environment more familiar than CL or REXX (although REXX is kind of fun). QSHELL is a full POSIX environment running on the iSeries. Use the command STRQSH to start QSHELL. You can have ksh or csh as a shell. Inside QSHELL, there is a command called "db2" that submits queries. So, you should be able to do something like this inside QSHELL:
system> VariableName = 'blah blah'
system> db2 "select * from TableName where Column = \'$VariableName\'"
You may have to fiddle with the quotes to get ksh to pass them correctly.
Also, inside QSHELL, you should have a full Perl installation that will allow you to use DBI to get data.
Some other ways to interact with data on the iSeries: query from the client with Python via ODBC; query from the client with Jython via JDBC; install Jython directly on the iSeries and then query via JDBC.
I have an oracle script that I am trying to convert to valid db2 syntax. Within this sql file I have various calls to other sql files passing in a parameter using the '#' syntax.
e.g.
#script1 param1
#script2 param2
Can anyone help me with valid db2 equivalent statements? Is there an equivalent run command in db2? is it possible to pass parameters to a sql script in db2?
thanks,
smauel
The thing you are after is the DB2 Command Line Processor (CLP).
If you want to execute a script, you would execute in the CLP:
db2 -vtf script1
-f tells the CLP to run command input from the given file.
Here's the full list of options.
Unfortunately db2 doesn't support passing parameters to a script. You would have to combine your db2 -vtf commands with other scripting commands (such as sed) to generate the scripts for you, as in this example.
1) place the filename.sql file in SQLLIB/BIN
2) run db2cmd
3) execute this to connect to the required db
db2 connect to *dbname* user *userid* using *password*
4) excute this command
db2 -vtf *filename.sql*
This should execute the sql statements in the file one by one. The sql statements must be ending with a semicolon
There is an easier way for passing in parameters, that works fine for us (it might not work with (complex) multiline sql statements).
Convert your sql-script into a shell script by adding 'db2 ' at the beginning of each line. Than you can use the standard variable replacement syntax from your shell in your scripts.
so instead of
insert ...
update ...
you will have
db2 insert ...
db2 update ...
Place file in one directory.
Open db2cmd.exe as administrator
Navigate to directory where you have place the script
type db2 -vtf `