I am trying to make use of Table declaration syntax and creating the same in Snowflake SQL.
I've gone through the snowflake community & documentations and all I could find is Table variable directly being assigned similar to SQL table variable or making use of a Table function.
generally Snowflake doesn't allow indexes nor type declarations.
other than that, you have two options:
use JS stored procedures, but they are not meant to return a range of values, all you can do is make a temporary table and put your set in there
use UDFs, that are (or well, can be) SQL and can return a table, but have a limited set of functionality
Related
I am migrating this Oracle command to PostgreSQL:
CREATE SYNONYM &user..emp FOR &schema..emp;
Please suggest to me how I can migrate the above command.
PostgreSQL does not support SYNOSYM or ALIAS. Synonym is a non SQL 2003 feature implemented by Microsoft SQL 2005 (I think). While it does provide an interesting abstraction, but due to lack of relational integrity, it can be considered a risk.
That is, you can create a synonym, advertise it to you programmers, the code is written around it, including stored procedures, then one day the backend of this synonym (or link or pointer) is changed/deleted/etc leading to a run time error. I don't even think a prepare would catch that.
It is the same trap as the symbolic links in unix and null pointers in C/C++.
But rather create a DB view and it is already updateable as long as it contains one table select only.
CREATE VIEW schema_name.synonym_name AS SELECT * FROM schema_name.table_name;
You don't need synonyms.
There are two approaches:
using the schema search path:
ALTER DATABASE xyz SET search_path = schema1, schema2, ...;
Put the schema that holds the table on the search_path of the database (or user), then it can be used without schema qualification.
using a view:
CREATE VIEW dest_schema.tab AS SELECT * FROM source_schema.tab;
The first approach is good if you have a lot of synonyms for objects in the same schema.
I would like to keep some computed columns in several tables and columns (PostgreSQL). The calculation is the same but there might be practically any number of tables and columns. So if the input is table1.field1 then the calculated field is table1.field1_calculated . And so forth. I was thinking on using triggers to maintain this, one trigger per field. This would require passing in the table and the field name as arguments into the function, assembling a SQL statement and executing it. I do not want to rely on plpgsql as that might not be available everywhere and everything I can find about dynamic SQL in PostgreSQL is a) old b) says you need plpgsql for that.
So
Is there a way in PostgreSQL 9.4+ or perhaps 9.5+ to create and execute dynamic SQL without plpgsql?
Is there a better way than triggering this function containing said dynamic SQL?
Ps. I am aware of the function/column notation trick but that doesn't really work here. For 2. I am suspecting rules might work but can't figure out how.
I'd like to write a ud-function in my SQL database in order to write procedure logging in a specific table among dbo tables.
I'd like this specific function could be called by any stored procedures inside my database.
I have no idea what kind of solutions I could use. I've learned that only 3 kinds of UDF are avalaible.
Any suggestions ?
Thanks.
A UDF always has to be side-effect free. That means that you cannot change data in a table from within a function.
If you are looking to call your logger from stored procedures, why not implement it as a stored procedure too?
I get the error "Incorrect syntax near the keyword 'truncate'." and not sure what's wrong with the syntax here, it's not obvious to me...probably something stupid but I need another set of eyes:
ALTER VIEW [dbo].[vw_All_Events]
AS
truncate table Event
Select [event_id]
,[site_id]
,[autogenerated]
,[creation_date]
,[last_update_date]
from Event
GO
A view only allows a single statement after the AS and it must be data retrieval (return a rowset). It can't be a different type including data definition, data modification, procedural, declarative, or any other.
You can do these things with a stored procedure, or a user-defined function (but can't do DDL & DML in a function).
In detail, a stored procedure allows flow-of-control statements like IF THEN ELSE BEGIN END WHILE RETURN. You can use DML to UPDATE, DELETE and INSERT. You can use DDL to CREATE and DROP tables and indexes, add columns and constraints, and so on. You can return multiple rowsets. You can execute dynamic SQL.
What are you trying to accomplish?
Better way, you use a stored procedure instead of view.
There are you write multiple statement and also get output.
You can only have select statements in views. Therefore, 'truncate' is an invalid command to use.
TRUNCATE does not work with views.
Check out this link
Funambol in its administration documentation has that for running on newer PostgreSQL instances which are more strict with types and casting you have to add those casts:
CREATE FUNCTION pg_catalog.text(bigint) RETURNS text STRICT IMMUTABLE LANGUAGE SQL AS 'SELECT textin(int8out($1));';
CREATE CAST (bigint AS text) WITH FUNCTION pg_catalog.text(bigint) AS IMPLICIT;
CREATE FUNCTION pg_catalog.text(integer) RETURNS text STRICT IMMUTABLE LANGUAGE SQL AS 'SELECT textin(int4out($1));';
CREATE CAST (integer AS text) WITH FUNCTION pg_catalog.text(integer) AS IMPLICIT;
The problem is that in the same database (in PostgreSQL terminology) I have also other schemas which applications broke because of those casts (with "operator is not unique: unknown || integer" and hint "Could not choose a best candidate operator. You might need to add explicit type casts.") while they worked before.
So one solution is of course to define additional database and have only Funambol in there. But I am wondering if is there a way to define those casts so that they take effect only in Funambol's schema and not in whole database.
No, it's not possible in the way you imagine it. Casts are identified by source and target type, and so if both types are one of the built-in types, all users of the database will see the same casts between them. The only workaround along that line would be to create clones of the built-in data types, but don't go there. ;-)
So you either need to seek a fix with Funambol, or separate your applications into different databases, and perhaps link them back together with something like dblink.