BigData

How to Execute HBase Commands from Shell Script? – Examples

Shell scripting is one of the widely used scripting language to automate day to day activities. Usually, Linux shells are interactive, they accept command as input from users and execute them. However, it will become repetitive as you have to type in all commands each time on terminal. Instead, you can bundle those commands in shell script. In this article, we will check how to execute HBase Commands from Shell Script with an example. Why Shell Script is Required? There are many reasons to use Linux shell scripting: It helps…

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June 6, 2019
BigData

Methods to Access Impala Tables from Python

Apache Impala is an open source massively parallel processing (MPP) SQL query engine for data stored on bigdata Hadoop. Cloudera Impala provides fast, interactive SQL queries directly on your Apache Hadoop data stored in HDFS or HBase. In addition to using the same unified storage platform, Impala also uses the same metadata, SQL syntax (Hive SQL), ODBC driver, and user interface as Apache Hive. In this article, we will check different methods to access Impala tables from python program or script. The methods we are going to discuss here will help you to connect Impala…

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June 4, 2019
BigData

Impala Delete from Tables and Alternative Steps

Data warehouse stores the information in the form of tables. You may have to delete out-dated data and update the table’s values in order to keep data up-to-date. These performance critical operations are critical to keep the data warehouse on bigdata also when you migrate data from relational database systems.  In this article, we will check Impala delete from tables and alternative examples. Impala Delete from Table Command Cloudera Impala version 5.10 and above supports DELETE FROM table command on kudu storage. This command deletes an arbitrary number of rows…

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June 2, 2019
BigData

SQL SET Operator MINUS Alternative in Impala

The SQL set operators are used to combine data from two or more SELECT statements. The set operators can combine only similar data sets. Here similar data set literally means the number of columns and its data type should match, otherwise you must explicitly type cast the types of the values or columns in the SELECT statements. Just like Apache hive, Impala support only UNION and UNION ALL set operator, INTERSECT and MINUS are not supported as of now. In this article, we will check SQL set operator MINUS alternative…

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May 31, 2019
BigData

Cloudera Impala Merge Statement – UPSERT Command

The MERGE query or statement in SQL is used to perform incremental load. With the help of SQL MERGE statement, you can perform UPDATE and INSERT simultaneously based on the condition. i.e. you can update old values and insert new records. The merge command is widely used in incremental load where you have to update old records and insert new records if any. In this article, we will check Cloudera Impala Merge Statement along with some Impala native UPSERT command. In SQL world, the merge statement is also referred to…

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May 30, 2019
BigData

Impala Dynamic SQL Support and Alternative Approaches

Dynamic SQL lets SQL statements be created and execute at run time, i.e. you can build SQL queries based on the user or application input and execute them to provide required output. For examples, pass a session specific value to the Impala queries dynamically during runtime. In this article, we will check how to build Cloudera Impala Dynamic SQL queries and how to execute them. Most of the relational databases like Netezza, Teradata, etc. supports stored procedure that will allow you to build and execute dynamic queries. Impala Dynamic SQL…

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May 29, 2019
Vertica

Vertica Update Join Syntax – Update using another Table

In a data warehouse, application may have various data sources. All these data sources are stored in tables in the database. Data is collected over the time and it may or may not be accurate. In some cases, you may want to update the table values based on the data available in another table over same or other database on the same server. For example, in a case of slowly changing dimension type 2, you may want to update the dimension table using a stage table that we created to…

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May 28, 2019
BigData

Hive Dynamic SQL Support and Alternative

Dynamic SQL queries are created on the fly and executed. Dynamic SQL lets SQL statements be defined and execute at run time, i.e. you can build SQL queries based on the user input and execute them to provide required output. For examples, pass a session specific value to the HQL queries dynamically during runtime. In this article, we will check how to build Apache Hive Dynamic SQL queries and how to execute them. Hive Dynamic SQL Support Apache Hive version 1.x and Cloudera impala does not support dynamic SQL, you…

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May 27, 2019
Vertica

Vertica Dynamic SQL Support and Alternative

Vertica dynamic SQL lets SQL statements be defined and run at run time, i.e. you can build SQL queries based on the user input and execute them to provide required output. For examples, pass a  date value or session specific values to the SQL queries dynamically. Most of the modern day databases such as Netezz, Oracle, etc support dynamic SQL as a part of stored procedure or functions. Unfortunately, Vertica database does not provide support for dynamic SQL. Hopefully, future versions of Vertica database may provide support to the dynamic…

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May 26, 2019
General

Execute Java from Python, Syntax and Examples

As per most of the surveys, Python is one of the fastest growing programming language. From web-development to complex scientific calculation, Python is being used in almost all fields. Similar to Python, Java is also one of the widely used programming languages. In this article, we will check how to get access to Java libraries from Python programs. There are lots of modules available to execute Java from Python. We will be discussing one of the such easiest module in this article. Jpype Python Module Python provides many modules that…

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May 24, 2019