DWgeek.com

How to Alter Redshift Table column Data type? Explanation

Amazon Redshift handles petabytes of data without any resource contention. Redshift support many data types to store data into Redshift table. As of now, you can alter Redshift table to increase the size of varchar column. However, Amazon Redshift does not support alter Redshift table column to a different data type for now. This feature may be added in later release for now we will check the alternative to change redshift table column data type. How to Alter Redshift Table column Data type? Currently, there is no way to change…

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June 20, 2017

Redshift

Amazon Redshift Distribution Types and Examples

Amazon Redshift is a cluster of nodes with separate disks, memory and CPU. Redshift distributes optimally across all the nodes based on the type of distribution you choose on the table or materialized views. In this article, we will learn about amazon redshift distribution types and some of examples. Amazon Redshift Distribution Types There are three distribution types available in the Amazon Redshift; EVEN, KEY, ALL and AUTO. You can choose any methods based on your requirement and type of joining that you are going to perform on the tables.…

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June 20, 2017

Netezza

Netezza find Database Objects – nz_find_object

If you are working on the huge data warehouse and that requires to create thousands of dimension and fact tables in hundreds of databases. You may want search for existence of particular table in hundreds of databases available in Netezza data warehouse appliance, this manual process is time consuming. In this article, we will discuss on Netezza find Database Objects to search the objects. Netezza find Database Objects – nz_find_object Luckily, IBM has provided a script nz_find_object, that can be used to find the objects in Netezza data warehouse appliance.…

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June 9, 2017

Netezza

Generate Netezza View DDL using nz_ddl_view

If you are working as a Netezza admin or developer then you may be asked to get DDL or definition of all views available in the particular database. You may have to generate view DDL when you are performing the reverse engineering too. In this article, we will discuss on how to generate Netezza view DDL using nz_ddl_view. Generate Netezza View DDL using nz_ddl_view If you are looking for the tool or script to generate the Netezza DDL or definition, then it might be your lucky day. IBM has provided script…

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June 7, 2017

Redshift

Amazon Redshift Architecture and its Components

Amazon Redshift Architecture is a shared nothing MPP architecture. The architecture is similar to the other MPP data warehouse systems such as Netezza, MS PDW, Greenplum etc. Amazon Redshift is a result of database integration, processing CPU and storage in a system. Amazon Redshift architecture is depicted in below diagram: SQL Client applications There are many SQL client applications that you can use to connect and query data stored in Amazon Redshift database: SQL Workbench/J: It is a free, open-source SQL client application for Windows, MacOS and Linux. pgAdmin: provides a psql, another…

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June 6, 2017

Redshift

Redshift Analytic Functions and Examples

Redshift analytic functions compute an aggregate value that is based on a group of rows in the tables. A Redshift PostgreSQL analytic function works on the group of rows and ignores the NULL in the data if you specify explicitly in the function. Redshift is basically a data warehouse analytics system and provides many useful functions that can perform day to day aggregations that save lot of times during the development. Usage of Redshift analytic function improves the performance of the query. Frequently used Redshift analytical functions are as follows:…

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June 5, 2017

Netezza

Run Netezza SQL Script File using nzsql Variable Substitution

Netezza allows the variable substitution using -v option in Netezza nzsql queries. The variable substitution is very important when you are calling the Netezza nzsql scripts from shell or any other scripting language. You can pass the values to query that you are calling using -v option. In this article, we will see how to run Netezza nzsql script file using nzsql variable substitution. We also see some of the working examples that uses the Netezza variable substitution method. Run Netezza SQL Script File using nzsql Variable Substitution You can set…

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June 4, 2017

Netezza

Netezza Conversion Functions and Examples

Netezza supports various conversion functions. Below are some of commonly used Netezza conversion functions. These functions uses common calling functions i.e. the first argument is the value to be formatted, and the second argument is a template that defines the output or input format. Read: nzsql command and its Usage Netezza Analytics Functions and Examples Explicit and implicit Netezza Type Casting With Examples Netezza Data Functions and Examples How to Resolve Netezza SPU Swap Partition Error Netezza Cast Function You can convert any data type to other using Netezza cast…

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June 3, 2017

BigData

Sqoop Command with Secure Password

Sqoop commands allows you to exchange the data between Hadoop and relational databases such as Netezza, Oracle etc. Sqoop required the password to connect to various databases and of course it has to be secured. In this article, we will discuss on various ways to execute the Sqoop Command with Secure Password. Read: Sqoop import Relational Database Table into HBase Table Import data using Sqoop Export data using Sqoop Sqoop Architecture – Mappers with No Reducers Sqoop Command with Secure Password Below are the some of the methods that we can…

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June 3, 2017

Netezza

Netezza DECODE Function Syntax and Examples

Netezza supports the DECODE function and it is similar to DECODE function in other relational databases such as Oracle, SQL Server, MySQL, Redshift etc. You can use the Netezza DECODE function to implement if-then-else statement in Netezza nzsql. This command is a short-hand form of Netezza CASE function. Netezza DECODE Function Syntax DECODE (expr, expr_val1, ’expr_rep1’, expr_val2, ’expr_rep2’, expr_val3, ’expr_rep3’, ’else-expr’) ; Execution Flow: If 'expr' is equal to expr_val1 then ’expr_rep1’ is returned, if 'expr' is equal to 'expr_val2' then ’expr_rep2’ is return, if 'expr' is equal to 'expr_val3'…

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June 3, 2017