EXTERNAL TABLE Archives - Page 2 of 2

Different Extraction Methods in Data Warehouse

Extraction is the first step of the ETL(Extract, Transform and Load) process. Once the data is extracted, you can transform it and load to target data warehouse. Extraction is the process of extracting data from the source system for further use in the data warehouse environment. Related Reading: Data Warehouse Fact Constellation Schema and Design Star Schema model in Data Warehouse Snowflake Schem Model in Data Warehouse Data warehouse is an OLAP system, typically source system includes the transaction business processing application. For example, it could be sales order entry…

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September 16, 2016

Netezza

Netezza External Table and Examples

A Netezza external table allows you to access the external file as a database table, you can join the external table with other database table to get required information or perform the complex transformations. External table script can be used to access the files that are stores on the host or on client machine. If the files are stored on the client machine, Netezza uses REMOTESOURCE option to access those files. Netezza External Table Syntax Below are the various syntax types that you can use to create external table in…

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September 6, 2016

Netezza

Commonly used Netezza Utilities

It is very easy to perform the ETL (Extract, Transform and Load) functionalities in Netezza. Netezza supports utilities those can be used to perform the ETL/ELT operations. Below are some of commonly used Netezza utilities: Read: Commonly used Netezza Basic Commands nzload utility nzload is bulk data load utility available in Netezza. This utility supports loading data from flat file to Netezza database tables. Below is the syntax and usage: Usage: nzload -host <host> -db <database> -u <username> -pw <password> -t <target_table_name > -df /user/home/flat_file.txt by default, nzload supports '|'…

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September 4, 2016

Netezza

List of Netezza Data Types and Best Practices

Data type is an attribute that specifies type of data of any object. Each column, variable and expression has related data type in SQL. However, different database offers the different data types for columns. Netezza data types are almost similar to what the traditional RDBMS supports. When you issue Netezza create table command each column in a database tables has to have name and a data type associated with it. The data type is based on the types of data which are stored inside the each column of the table.…

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September 2, 2016

Greenplum

Greenplum Unloading Data Examples

Greenplum can supports unloading large amounts of data. It also supports single file, non-parallel export for small amounts of data. Greenplum unloading data is supported by various methods such as COPY TO command and create writable external tables. In this post you will learn how to unload data from Greenplum Database using parallel unload (writable external tables) and non-parallel unload (COPY) Read: Greenplum Data Loading Options How to Export Vertica Query Results into CSV? Create Writable External Tables Greenplum writable external table uses the Greenplum distributed file server, gpfdist to create file…

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August 20, 2016

Greenplum

Greenplum Data Loading Options

Being a MPP server, Greenplum supports parallel data loading for large amounts of data. It also supports single file, non-parallel import for small amounts of data. Greenplum data loading is supported by various methods as follows. Read: Greenplum Architecture Data Loading Options Greenplum supports following tools for loading 1. Greenplum data Loading with gpload Command The gpload Greenplum data loading utility is an interface to external table parallel loading feature. gpload uses a load specification or layout defined in a YAML formatted control file to load data into the target table…

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August 19, 2016