Postgres Function Variables

#Environment Variables. If you are considering moving from a MSSQL environment to PostgreSQL, this blog provides a high level overview of what you should know to migrate between the two. Oracle) I. You can see effective use of PostgreSQL's possibilities on this page. Run the following command in the root directory of your Node-RED install. To substitute the variable, use. get_window_object(), which provides the following interfaces: WindowObject. postgres=# postgres=# -- Name: "raise_test" Type: FUNCTION Owner: postgres postgres=# CREATE FUNCTION "raise_test" RETURNS integer AS ' postgres. It shows how to use SQL statements to query, insert, update, and delete data in the database. 2 and above. PostgreSQL offers a number of specific datatypes. 0, PostgreSQL 8. i went for crosstab but it doesnot support variable number of. User GUCs can store and load TEXT temporarily (i. Pushes a new element onto the end of an existing PostgreSQL array. Postgres uses 'now'::timestamp for current transaction start date and time in session's timezone, which ACS/pg has conveniently wrapped in a function named sysdate(). SQL is a language where one task can be solved multiple ways with different efficiency. ACS/pg also includes a Tcl procedure named db_sysdate which should be used every time the sysdate term appears. Is there a way to do this? I can list all the functions from pg_proc, however there is nothing there which provides the code of the function, so therefore I can't query if it mentions a table. , to insure the highest levels of performance. Update pots (including getting rid of SVN) 2018-09-16 21:52 Regina Obe * [r16815] Prepping for 2. i went for crosstab but it doesnot support variable number of. default) schema will always have the. 3 (or use the beta) Use the plv8 extension. CREATE EXTENSION session_variables; If you've upgraded your cluster to PostgreSQL 9. If you have used PostgreSQL JSON functions and operators you will notice that FOR JSON clause is equivalent to JSON creation functions such as row_to_json, or json_object. A PostgreSQL function can accept a variable number of arguments with one condition that all arguments have the same data type. This chapter describes table functions. Unlike sql functions which currently require you to refer to variables by their ordinal position $1, $2, $3 etc. Variables are local for FOR statement and they are created in specified namespace if namespace is known. You are already using global variables in your program so why not extend their use ?. Syntax of the REPEAT() function. The most important function in the library is ECPGdo, which takes care of executing most commands. PostgreSQL functions are also known as PostgreSQL stored procedures. js is a "batteries included" SQL query builder for Postgres, MSSQL, MySQL, MariaDB, SQLite3, Oracle, and Amazon Redshift designed to be flexible, portable, and fun to use. These variables are filled by implicit FETCH statement every statement cycle. When using SQL Relay bind functions, to refer to an Oracle, Sybase or MS SQL Server bind variable, you should use its name without the preceeding colon. In this article we shall cover all variants of this. PostgreSQL is a powerhouse in its own right, but it is also extensible. su -l postgres -c "psql -c \"CREATE DATABASE graphite WITH OWNER. CRUD functions, similar to SQL stored procedurs, for postgresql tables? Asynchronous query execution; How to guard PostgreSQL from overcharged and/or malicious (read-only) queries? Versatile Software Developer needed in Los Angeles area "parameterized views" or return-type-inferring SQL functions?. c in the Linux kernel before 2. This is an excerpt from the script that I was creating: insert into businesshours values ($1,$2,$3); return ''0''; end;. Nodejs and PostgreSQL Tutorial with Example July 11, 2016 by pushker PostgreSQL is one of the popular open source [Object]- relational database, PostgreSQL supports json datatypes as well as you can define your own datatypes so its a good choice to use in your project. Local Variables All the variables we have used thus far have been local variables. id),' 999') ELSE '' is not slow because COUNT() is called twice. name from test_table t where t. Was causing problems with po conversion. In case you're on PostgreSQL 9. Here's what we needed to change to get the example to work:. The functions given below are spatial aggregate functions provided with PostGIS that can be used just like any other sql aggregate function such as sum, average. schema attribute set to None. The “default” schema on PostgreSQL is that which is returned by the PostgreSQL current_schema() function. In the function, we will increase the value of the first argument by the second argument. Explicitly defining the encoding of your strings in every script will save you a lot of headaches. CREATE FUNCTION postgres=# postgres=# postgres=# SELECT stock_amount. NET Access to PostgreSQL About. Postgresql Declare Variable Outside Function. 1 Datatypes. Do take this feature for a spin and let us know what you think! Support for more functions types and for functions in mutations is on its way. If you are calling the procedure from within another stored procedure or function, you can also pass a routine parameter or local routine variable as an OUT or INOUT parameter. This statement detect all columns in SQL query and implicitly creates correspondent variables with correct type. The default configuration PostgreSQL ships with is a very solid configuration aimed at everyone's best guess as to how an "average" database on "average" hardware should be setup. pgAdmin is the most popular and feature rich Open Source administration and development platform for PostgreSQL, the most advanced Open Source database in the world. ParameterList, boolean). We can create a new function named inc that accepts two arguments. Learn Pl/SQL in a simple way. 7, “Server System Variables”. Different databases have different writtings:. Porting from Oracle to PostgreSQL by Paulo Merson February/2002 If you are starting to use PostgreSQL or you will migrate from Oracle database server, I hope this document helps. In this post, I am sharing tips like how to use a psql session variable to make your queries more dynamic in PostgreSQL. PRAGMAs that return results and that have no side-effects can be accessed from ordinary SELECT statements as table-valued functions. Using select into to set variable value : Set Value « Postgre SQL « PostgreSQL. Created variables live only in the current user session. This chapter provides a list of the PostgreSQL SQL commands, followed by the precise syntax rules for each of these commands. autocommit is a session variable and must be set for each session. --Richard Huxton Archonet Ltd. C has the advantage of speed, of course. SQL Server: -- Add 1 day to the current date November 21, 2012 SELECT DATEADD(day, 1, GETDATE()); # 2012-11-22 17:22:01. I want to have a pivot like function in which i should have variable number of columns. The behaviour of some functions is different between Oracle and PostgreSQL. Is it still true (the posts I see on this subject are quite old) that I can not do so in Postgres outside of a stored procedure/function? And if so, what's the reason of not adding this feature? Seems very useful to me. Thanks in advance, ~Harpreet. User GUCs can store and load TEXT temporarily (i. I have published a fix on the tip of each major version branch of all affected versions as well as a fix on each minor version branch of [email protected] String values can be converted to a different character set using CONVERT(). This is different from a constant in that the variable's value can be changed later. variables are only available in code blocks or as a user-interface feature. By default, string comparisons are not case-sensitive and use the current character set. 2, PostgreSQL 9. Where web developers and designers learn and share how to design websites, build mobile applications, create WordPress themes, write code, HTML, JavaScript, PHP, Java, and much more!. 3, PostgreSQL 9. Understanding the process. Try it out. An easy-to-use multi SQL dialect ORM for Node. Both of these are examples of finding the greatest running total. The PL/pgSQL functions have several special variables that are automatically created in the top-level block. Variables or Magic words are strings of text that MediaWiki associates with a return value or function, such as time, site details, or page names. This can be useful if your application already has a way to manage config values or you don't want to use environment variables. Hi, I am facing issue while calling a function stored in postgres Database using call DB procedure step. Leave a reply. PostgreSQL/SQL standard count characters in SUBSTR starting from 1. A PostgreSQL function or a stored procedure is a set of SQL and procedural statements (declarations, assignments, loops, flow-of-control etc. A PL/pgSQL variable is a meaningful name for a memory location. Access control for custom functions. CREATE DATABASE -- Creates a new database in PostgreSQL. gitignore file from trunk 2012-05-04 08:08 strk * NEWS: Convert NEWS to UTF8 (#1801) 2012-05-04 08:02 strk * NEWS, postgis/lwgeom_functio. Note: Before PostgreSQL 8. Try each date function in. As you can see in the example function, PostgreSQL allows us to read from and write to any field in the NEW object, before it gets saved. Additionally, you should use the mb_ internal_ encoding() function at the top of every PHP script you write (or at the top of your global include script), and the mb_http_output() function right after it if your script is outputting to a browser. By default, created variables are not transactional (i. A Node-RED node to query PostgreSQL. However, the C names of all functions must be different, so you must give overloaded C functions different C names (for example, use the argument types as part of the C names). If unsure why, check the changelog for Postgres 8. The list below represents a combination of the following sources of SQL reserved words:. CREATE DATABASE -- Creates a new database in PostgreSQL. com, PostgreSQL is the DBMS of the year 2017. In PostgreSQL, functions that have different parameters can share the same name. We can create a new function named inc that accepts two arguments. If it doesn't exist, functions return FALSE. id = x; But better use one of the first two, clearer methods, as @Pavel commented. yml by adding an environment object property in the function configuration. If you want to install session_variables and all of its supporting objects into a specific schema, use the PGOPTIONS environment variable to specify the schema, like so: PGOPTIONS=--search_path=extensions psql -d mydb -f session_variables. Most PostgreSQL functions accept connection as the optional first parameter. 2, PostgreSQL 9. psqlODBC - PostgreSQL ODBC driver. For migration first we need to install oracle database and ora2pg software and DBD oracle packages. The variable name must begin with two dashes (--) and is case sensitive! The syntax of the var() function is as follows:. Customer has a requirement to create a report which calls custom PostgreSQL function with 'character varying[]' parameter type (array of variable string). Here's our same script from above modified to use programmatic (hard-coded in this case) values. printing variable values in pl/pgsql functions. Using RAISE NOTICE. "How to declare local variables in PostgreSQL? It is very easy to declare local variables in SQL Server but it seems not possible in PostgreSQL. The variable fileScope can be changed or called from anywhere within this file, whereas the localScope variable only exists inside the function doSomething(). Both of these are examples of finding the greatest running total. The Postgres (postgresql. Try each date function in. This post explores the different ways to deal with application state when writing business logic in serverless functions. I will walk you through all the steps in detail. 13 Using Pipelined and Parallel Table Functions. Switch to the new look >> You can return to the original look by selecting English in the language selector above. It is one of the features that makes building aggregate functions wicked easy in PostgreSQL with no messy compiling required. PostgreSQL COUNT Function − The PostgreSQL COUNT aggregate function is used to count the number of rows in a database table. This page is about usage of standard magic words; for a technical reference, see Magic words. 3, PostgreSQL 9. One of the main features I love about PostgreSQL is its array support. conf This post has been updated with new code that uses temporary table – the code is at the end of post! There was this question on Stack Overflow. The outer block is labeled with the function's name, meaning that parameters and special variables can be qualified with the function's name. The \/command-line tool\/ reads JSON from stdin and writes prettified JSON to stdout. Edited by Andrii Lototskyi Install. This chapter provides a list of the PostgreSQL SQL commands, followed by the precise syntax rules for each of these commands. In PostgreSQL, bind variables are numbers preceeded by a $ sign. It also explains the generic datatypes ANYTYPE, ANYDATA, and ANYDATASET, which are likely to be used with table functions. Execute a statement for each row of a table. Note that this could potentially result in run-time. That is, we define the fields of the SETOF rows that the function will return. file - the quoted file name that the function was called with. This function will simply increment the value and return it. 1, PostgreSQL 9. Trigger will eventually call a function which is written in PL/SQL or PL/pgSQL or any other compatible language. To create one, first obtain a window object by calling plv8. org) web site has some information not appearing in the distribution. createFastpathParameters(int) - Method in class org. su -l postgres -c "psql -c \"CREATE DATABASE graphite WITH OWNER. Without control, you risk exposing sensitive information about your company or, worse yet, your valuable customers. conf to add your own custom_variable_classes, you can do more or less the same thing using some very simple functions. In the previous post, I shared shell script like store psql result into record array. I'm writing a javascript function which will take in a parameter of a watershed id from another function. Postgres Plus Advanced Server Oracle Compatibility Developer's Guide : 4. The following table lists all window functions provided by PostgreSQL. html 2019-08-29 15:08:41 -0500. Red Hat Enterprise Linux 3 Red Hat Enterprise Linux 4 Red Hat Enterprise Linux 5 PostgreSQL 7. 1, PostgreSQL 9. Can anyone help me in finding out where i am doing wrong. In the previous example, you created one cursor (not just a cursor variable) named next_rental and a cursor named next_tape. US, March 2015: Fun with Functions, by Example; DCPUG/Data Wranglers DC, May 2015: Easy Statistical Analysis in PostgreSQL with PL/R. Function predefined variables. It is designed to handle a range of workloads, from single machines to data warehouses or Web services with many concurrent users. Note that some aggregate functions such as AVG(), MIN(), MAX(), SUM(), and COUNT() can be also used as window functions. psqlODBC - PostgreSQL ODBC driver. This is called function overloading, which is similar to function overloading in C++ or Java. But here in function we cannot fire commit as – it is not allowed in mysql (explicit implicit commit). The CAST() function converts a value of any type into a value that has a specified type. From a syntax perspective, PostgreSQL supports only the FUNCTION keyword. 2 and above. Database security is the single biggest concern with today's Web-based applications. Variables are local for FOR statement and they are created in specified namespace if namespace is known. So, for example, assigning now() to a variable of type timestamp causes the variable to have the time of the current function call, not the time when the function was precompiled. 4 function to return result set of multiple select queries if so then how?. Amazon Redshift and PostgreSQL have a number of very important differences that you must be aware of as you design and develop your data warehouse applications. PostgreSQL SPLIT_PART() Function with Example : The PostgreSQL split_part function is used to split a given string based on delimiter and pick out the desire field from the string, start from left of the string. Naming the parameter in the CREATE FUNCTIONcommand tends to make the function more readable to many, however, it is not mandatory. All rights reserved. You can use PL/PgSQL if you want variables, in a function or a DO block. You can use various datetime expressions or a user-defined DATEDIFF function (UDF) to calculate the difference between 2 datetime values in seconds, minutes, hours, days, weeks, months and years in PostgreSQL. Posts have a 200-word limit, and posting is open to any Rocketeer as well as select friends of the team. Press question mark to learn the rest of the keyboard shortcuts. Merge: b411f36bca 87442a536e Matthias Kuhn 2019-01-15 Merge pull request #8835 from rldhont/bugfix-oracle-compile-expression-like-218 [Bugfix][Oracle] Add ESCAPE when compiling LIKE rldhont 2019-01-11 [Bugfix][Oracle] Add ESCAPE when compiling LIKE The oracle SQL documentation specifies that *there is no default escape character* and *the escape character, if specified, must be a character. You’ve got three options if you actually want to do something with it: Wait for PostgreSQL 9. js application. Database Research & Development: Use PostgreSQL RAISE Statements to debug your query and function performance. Actually not the variable completely, but the config "class" which is essentially the prefix. 4, PostgreSQL 9. Unless otherwise noted, all of the functions listed below work on all of these types, but be wary of potential effects of automatic space-padding when using the character type. node-postgres is a collection of node. Well, actually there is, but they're not suitable for general use within queries. Here's what we needed to change to get the example to work:. Generated on Fri Sep 20 2019 18:14:18 for PostgreSQL Source Code by 1. PL/SQL Functions What is a Function in PL/SQL? A function is a named PL/SQL Block which is similar to a procedure. 3/PostGIS which is storing some polygons. This quickstart demonstrates how to connect to an Azure Database for PostgreSQL using a Node. type definition; functions and operators. SELECT function_identifier (arguments); variable_identifier:= function_identifier (arguments); The use of assignments and SELECT statements to execute functions is standard in PL/pgSQL because all functions in a PostgreSQL database must return a value of some type. This object should contain a key-value pairs of string to string:. I have two main problems that seem to be variations on the same theme of running dynamic SQL from a variable with the EXECUTE statement and returning the results back to a variable defined in the calling function. For example, if the function returns a trigger, then several variables, such as NEW, OLD, and TG_OP, are created. PRAGMAs that return results and that have no side-effects can be accessed from ordinary SELECT statements as table-valued functions. 4 function to return result set of multiple select queries if so then how?. If it doesn't exist, functions return FALSE. Created variables live only in the current user session. For migration first we need to install oracle database and ora2pg software and DBD oracle packages. Any SQL functionality that is native to your dialect can be leveraged in the sql: parameters within LookML, or as derived tables. Heroku Postgres offers a variety of plans, spread across different tiers of service: hobby, standard, premium, and enterprise. Well, actually there is, but they're not suitable for general use within queries. I have attached the sample. Stack Exchange Network. "WhiteHat Security utilizes PostgreSQL and Ubuntu in a high velocity OLTP environment with HP and Apple hardware. Downloads are available in source and binary formats at the PostgreSQL downloads site. All variable-length types must begin with a length field of exactly 4 bytes, and all data to be stored within that type must be located in the memory immediately following that length. Instructor Dan Sullivan also introduces more detailed analysis techniques using discreet and continuous percentiles to help segment data, and correlations between variables to identify relationships. In this section, we will learn how to execute the PostgreSQL function and Stored procedure in Python. PostgreSQL Tools. Our function returns a 'SETOF sales'; which means we're returning a set of the type 'sales', every table in PostgreSQL is a composite type consisting of the types of it's individual columns. 9 when using the tiffinfo tool to print crafted TIFF information, a different vulnerability than CVE-2017-18013. 4 and later) can also return a table. A variable's default value is evaluated and assigned to the variable each time the block is entered (not just once per function call). We can create a new function named inc that accepts two arguments. Execute a statement for each row of a table. postgres=# postgres=# -- Name: "raise_test" Type: FUNCTION Owner: postgres postgres=# CREATE FUNCTION "raise_test" RETURNS integer AS ' postgres. We've made the data for each example available in the Mode Public Warehouse. Update pots (including getting rid of SVN) 2018-09-16 21:52 Regina Obe * [r16815] Prepping for 2. table/column names) to lower-case values at object creation time and at query time. Oracle allows SUBSTR(text, 0, Y) also and treats its like SUBSTR(text, 1, Y). SQL functions can be declared to accept variable numbers of arguments, so long as all the "optional" arguments are of the same data type. So if you seed the function with something like, “Postgres is super” and tell it you want the first 8 characters of that string, SUBSTRING("Postgres is super", 1, 8) returns “Postgres”. How should i define this variable first and how to push the result of the query fired on table xyz. The list below represents a combination of the following sources of SQL reserved words:. Introduction to MySQL GROUP_CONCAT() function. conf prior to being used, so it limited its usability somewhat. Database Research & Development: Use PostgreSQL RAISE Statements to debug your query and function performance. PL/pgSQL Declaration : All variables must be declared in the declarations section of the block. One of the common use cases for using OUT parameters is to be able to return multiple outputs from a function without having to declare a PostgreSQL type as output of the function. NET Data Provider for PostgreSQL, it allows programs written in C#, Visual Basic, F# to access the PostgreSQL database server. If the driver is a true Unicode driver, it can understand "W" function calls and the Driver Manager can pass them through to the driver without conversion to ANSI. EnterpriseDB Postgres is the most complete open source-based data platform. Its now possible to call SQLNumResultCols after SQLPrepare. printing variable values in pl/pgsql functions. It is implemented in 100% C# code, is free and is open source. 4 and later) can also return a table. PL/pgSQL variables can have any SQL data type, such as integer, varchar, and char. It shows how to use SQL statements to query, insert, update, and delete data in the database. This can be useful if your application already has a way to manage config values or you don't want to use environment variables. The optional arguments will be passed to the function as an array. Porting from Oracle to PostgreSQL by Paulo Merson February/2002 If you are starting to use PostgreSQL or you will migrate from Oracle database server, I hope this document helps. CREATE GROUP -- Creates a new PostgreSQL group within the database. PostgreSQL functions (version 8. This expression: CASE COUNT(measurement. confor has been received from the postmaster. The variable fileScope can be changed or called from anywhere within this file, whereas the localScope variable only exists inside the function doSomething(). CRUD functions, similar to SQL stored procedurs, for postgresql tables? Asynchronous query execution; How to guard PostgreSQL from overcharged and/or malicious (read-only) queries? Versatile Software Developer needed in Los Angeles area "parameterized views" or return-type-inferring SQL functions?. Let's take a quick look at the 'varlena' data structure used internally by PostgreSQL to represent variable length data structures. Heroku Postgres offers a variety of plans, spread across different tiers of service: hobby, standard, premium, and enterprise. PostgreSQL - DATE/TIME Functions and Operators - We had discussed about the Date/Time data types in the chapter Data Types. su -l postgres -c "psql -c \"CREATE DATABASE graphite WITH OWNER. Note: PostgreSQL automatically folds all identifiers (e. What is true is that C cannot return more than one variable from a function, but there are ways round that. All rights reserved. These functions can be used in SQL statements or queries in PostgreSQL. When an asterisk(*) is used with count function the total number of rows returns. The hard work of aggregating the data is the part where the key values are brought together. CREATE FUNCTION postgres=# postgres=# postgres=# SELECT stock_amount. When you execute the following functions within a transaction block (BEGIN … END), the function returns the start date or time of the current transaction, not the start of the current statement. 2 you can just set your custom class variable as you are doing currently, no need to worry about changing postgresql. We've made the data for each example available in the Mode Public Warehouse. SQL Aggregate functions return a single value, using values in a table column. Currying is a shorthand notation for creating an anonymous function with a new scope that calls another function. PostgreSQL Regexp Functions With the substring( string from pattern ) function, you can extract part of a string or column. Additionally, you should use the mb_ internal_ encoding() function at the top of every PHP script you write (or at the top of your global include script), and the mb_http_output() function right after it if your script is outputting to a browser. PRAGMA functions. Our function takes two arguments, an employee and a car id, both being integers. A pseudo-type cannot be used as a column data type, but it can be used to declare a function's argument or result type. PostgreSQL also has a substring function, but the syntax is different than what you’re probably used to. "WhiteHat Security utilizes PostgreSQL and Ubuntu in a high velocity OLTP environment with HP and Apple hardware. You can issue almost all statements by building them up in a string and using EXECUTE. The following example illustrates the idea. I need to assign values to 2 variable as below in Postgres function. 4 Example - With Single Expression Let's look at some PostgreSQL sum function examples and explore how to use the sum function in PostgreSQL. Amazon Redshift and PostgreSQL have a number of very important differences that you must be aware of as you design and develop your data warehouse applications. For example. Our function returns a ‘SETOF sales’; which means we’re returning a set of the type ‘sales’, every table in PostgreSQL is a composite type consisting of the types of it’s individual columns. get_current_position() Returns the current position in the partition, starting from 0. Our function returns a 'SETOF sales'; which means we're returning a set of the type 'sales', every table in PostgreSQL is a composite type consisting of the types of it's individual columns. Function Parameters. SQL Functions with Variable Numbers of Arguments. ) that stored on the database server and can be invoked using the SQL interface. If it is not provided, the last opened connection is used. It’s a great way to trim your string down to a specific value or identify if one string is a part of the current string. Red Hat Enterprise Linux 5 The generic_file_splice_write function in fs/splice. Hi, I have a pl/pgsql in which i have to print various variable values during the execution of the function to see what values are getting populated. Following my tutorial on how to extract meta informations from Firebird SQL, I'm now going to show how to retrieve the same informations from PostgreSQL, using the INFORMATION_SCHEMA (available since PostgreSQL 7. 3, PostgreSQL 9. Triggers attached to TRUNCATE operation or views fire at the the statement level. For example. npm install node-red-contrib-postgres-variable. Oracle) I. PostgreSQL SUBSTRING() function with Example : The PostgreSQL substring function is used to extract a string containing a specific number of characters from a particular position of a given string. Next we 'DECLARE' the variables for use within our function. Where web developers and designers learn and share how to design websites, build mobile applications, create WordPress themes, write code, HTML, JavaScript, PHP, Java, and much more!. **General expressions** * **env(name)**: Gets an environment variable and returns its content as a string. In PostgreSQL, bind variables are numbers preceeded by a $ sign. This substitution happens during input processing in psql, so you can't (say) define a function that uses :'filepath' and expect the value of :'filepath' to change from session to session. id),' 999') ELSE '' is not slow because COUNT() is called twice. So user of function would not bother about any commit operation. These values are then referenced using the :variable_name format, enabling them to be queried within SQL. Strings in this context include values of the types character , character varying , and text. - okbob/plpgsql_check. 19 does not properly strip setuid and setgid bits when there is a write to a file, which allows local users to gain the privileges of a different group, and obtain sensitive information or possibly have unspecified other impact, by splicing into an inode in order to create an. **Date and Time expressions** * **epoch(date)**: Return the interval in milliseconds between the unix epoch and a given date value. Pipelined table functions include the PIPELINED clause and use the PIPE ROW call to push rows out of the function as soon as they are created, rather than building up a table collection. Postgres functions that return datasets Postgres functions that return data sets are poorly documented and their syntax might look a bit awkward to those of you used to SQL Server. Run enterprise Postgres at scale, break free from Oracle, or ease your cloud migration with EDB. Enter the following code and save the file as apg_email_function. This is an introduction to writing basic functions in PL/pgSQL. If it is not provided, the last opened connection is used. If you have a more specific. This is called function overloading, which is similar to function overloading in C++ or Java. The optional arguments will be passed to the function as an array. PostgreSQL functions are also known as PostgreSQL stored procedures. Understanding the process. Variables within psql work much the same way as variables within UNIX and Linux shell programs, such as bash. The 'events' are INSERT, DELETE, UPDATE or TRUNCATE. The major difference between a procedure and a function is, a function must always return a value, but a procedure may or may not return a value.