DWgeek.com

Access HBase Tables from Impala working Examples

As you know Hadoop Hive or Impala does not properly support transaction data. HBase is best suited for the table which required lot of delete, update, insert etc. You may want to explore the data stored in the HBase table. This article, helps you to understand how to access HBase tables from Impala and we will check out process with an example. Read other article on loading HBase table from Hive: Loading HBase Table from Apache Hive Why you want to access the HBase tables from Impala? This is obvious…

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November 8, 2017

BigData

Cloudera Impala Type Conversion Functions and Examples

Impala has some very strict rules regarding data types for function parameters that you provide while executing it. Impala type conversion functions are used to explicitly convert the required format. For example, Impala does not convert DOUBLE to FLOAT, INT to STRING etc. In my other post, we have discussed on Impala date functions and examples. In this article, we will check out Cloudera Impala type conversion functions with an examples. Read: Commonly used Cloudera Impala Date Functions and Examples Impala Type Conversion Functions These type conversion functions uses common…

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November 8, 2017

BigData

Clouderal Impala SQL Join Types and Examples

Impala SQL Join is a clause that is used for combining specific fields from two or more tables based on the common columns. The joins in the Impala are similar to the SQL and Hive joins. Joins are used to combine rows from multiple tables. In this article, we will learn about different Impala SQL join types with examples. Different Impala Join Types Following are Different Hive Join Types INNER JOIN LEFT OUTER JOIN RIGHT OUTER JOIN FULL OUTER JOIN SEMI JOIN ANTI JOIN CROSS JOIN Below are the tables…

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November 7, 2017

Netezza

Access Netezza Database, Tools and Examples

There are many ways to access Netezza database or host. You can use the nzsql command, you can also access the Netezza system by using tools such as Aginity, Squirrel and from windows system using nzsql.exe program if you have Netezza ODBC drivers installed. Access Netezza Database using nzsql Command You can use the nzsql command on the IBM Netezza host system or from a UNIX client system that can access the Netezza host. The client system should be configured with Netezza drivers in order to access the Netezza host.…

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November 6, 2017

Netezza

Netezza RECORD Type Variable, Usage and Examples

Just like other procedural language, Netezza supports RECORD type variables. Netezza RECORD type variable are similar to row types, but they have no predefined structure associated with it. You can use the record type only inside Netezza stored procedures (SP). They are used in selections and FOR loops to hold one database row from a SELECT operation. Read about Netezza Stored Procedure here: Netezza Stored Procedure and Examples IBM Netezza Control structures and usage Netezza Stored Procedure ARRAY Variables and Examples Netezza RECORD type Variable Declaration Below is the syntax…

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November 5, 2017

BigData

Hadoop – Export Hive Data with Quoted Values into Flat File and Example

In general, quoted values are values which are enclosed in single or double quotation marks. Usually, quoted values files are system generated where each and every fields in flat files is either enclosed in SINGLE or DOUBLE quotation mark. In this article, we will check how to export Hadoop Hive data with quoted values into flat file such as CSV file format. Quoted Value File Overview In the quoted values files, values are enclosed in quotation mark in case there is a embedded delimiter. For example, comma separated values file…

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November 5, 2017

Netezza

Export Netezza Data with Quoted Values into Flat File and Example

In general, quoted values are values which are enclosed in single or double quotes. Usually, quoted values files are system generated where each and every fields in flat files is either enclosed in SINGLE or DOUBLE quotation mark. In this article, we will check how to export Netezza data with quoted values into flat file such as CSV format. Quoted Value File Overview As mentioned in the previous section, quoted values files contains the values that are enclosed either in SINGLE or DOUBLE quotation mark. Generally, values are enclosed in…

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November 4, 2017

Netezza

Extract Netezza Table into Fixed-width file format and Example

Fixed width text files are special cases of text files. In a fixed width file, the format is specified by column widths, pad character and left or right alignment. In this format column width are in terms of units of characters. Fixed-width files has field (column) withe same predefined width in each file row, similar to a spreadsheet table. In this article, we will check how to extract Netezza table into fixed-width file format with a working examples. The examples of fixed width files would be telecom CDR (call detail…

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November 3, 2017

Data Warehouse

Data Warehouse fact-less fact Tables and Examples

A Data Warehouse fact-less fact table is a fact that does not have any measures stored in it. This table will only contain keys from different dimension tables. The fact-less fact is often used to resolve a many-to-many cardinality issue. Types of Fact-less fact tables in Data Warehouse? There are two types of fact-less fact tables Event capturing fact-less fact This type of fact table establishes the relationship among the various dimension members from various dimension tables without any measured value. For examples, Student attendance (student-teacher relation table) capturing table…

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November 2, 2017

BigData

Hadoop Security – Hadoop HDFS File Permissions

Hadoop HDFS file permissions are almost similar to the POSIX file system. In a Linux system, we usually create OS level users and make them members of an existing operating system group. But in Hadoop, we create directory and associate it with an owner and a group. Hadoop HDFS File and Directory Permissions The following sections show Hadoop HDFS file and directory permissions: Just like Linux operating system, Hadoop uses notation (r,w) to denote read and write permissions. There is an execute (x) permission for files but you cannot execute…

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November 2, 2017