Netezza Archives - Page 12 of 17

Netezza Query Tool Introduction, Features and Screenshot

Netezza supports JDBC, ODBC and OLEDB connectors. There are many free and paid Netezza query tool available in market. There most popular Netezza query tool includes Aginity workbench, WinSQL, SQuirrel SQL Client tool etc. Aginity Workbench Aginity Workbench is free, most popular and an easy-to-use application that enhances your performance when you are working with your Netezza data warehouse. If anybody think of Netezza query tool then first thing comes to their mind is Aginity workbench. This SQL database development tool offers unique capabilities that allow you to focus on…

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October 18, 2016

Netezza

Netezza ROWNUM Pseudo Column Alternative

If you are coming from Oracle database background, you will find it difficult in Netezza without ROWNUM pseudo column. The one possible solution to this is ROW_NUMBER() analytical function as Netezza ROWNUM pseudo column alternative. You can use ROW_NUMBER analytic function as a Netezza ROWNUM equivalent. I think most of the distributed databases does not provide the ROWNUM columns. There is a LIMIT clause to restrict the output but very difficult to assign the sequential numbers to the rows in the Netezza tables. Even Netezza Sequences also does not produce…

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October 16, 2016

Netezza

Changing Netezza Table Distribution key and Example

Choosing right distribution key is one of the important factor to improve the performance of Netezza server. If you have created the table with RANDOM distribution or with different column with lots of duplicate records then you should immediately change the distribution key otherwise that will reduces the performance. Changing Netezza table distribution key is process of redistributing the Netezza table using Netezza nzsql. Changing Netezza Table Distribution key and Example You can achieve the redistribution in couple of ways: Redistribute using CTAS Creating new table and loading data at…

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October 15, 2016

Netezza

Netezza Table Locking and Concurrency

You cannot explicitly lock the tables in Netezza. The Netezza SQL, however, uses implicit Netezza table locking when there is a DDL operation on it. For example, drop table command is blocked on the table if a DML commands are running on table and vice versa. Netezza uses the serializable transaction isolation to lock the table and is ACID property compliant. That ensures no dirty reads, no non repeatable reads. Read: How Netezza Updates Records in Table? Netezza Identify and Kill Table Locks nzsql Command and its Usage Netezza Best…

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October 12, 2016

Netezza

How Netezza Update Records in Tables?

Netezza update records operation is costlier. IBM Netezza does not perform updates, but rather does deletes the records and inserts updated values. When you run nzsql command to update record, Netezza marks the record being updated as logically deleted by setting current transaction value to the deletexid field, but does not delete it. This ensures that the database system adheres to the ACID properties of RDBMS SQL standards. How Netezza Update Records in Tables? Each record in Netezza contains two slots, one for createxid another for deletexid. Deletexid allows you…

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October 5, 2016

Netezza

Netezza Encrypt Password with nzpassword Command Utility

Database user accounts must be authenticated during access requests to the IBM Netezza database. You can secure the password by using Netezza encrypt password facility. Local authentication requires a password for every account which connects to the Netezza server. You must enter the clear text password, when you use Netezza CLI commands. You can set the environment variable NZ_PASSWORD to avoid the type of password every time but this variable also stores the clear text password. Read: Commonly used Netezza Utility Netezza Best Practices to Improve Performance Netezza nzsql Commands and…

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October 4, 2016

Netezza

Netezza Fixed-Width File Loading and Examples

Fixed width text files are special cases of text files where 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. In this post we will learn about Netezza Fixed-Width file loading. Fixed-Width File Overview All data is a series of byte-sequences and has an associated data type, used here as a conceptual or abstract attribute of the data. Fixed-length format files use ordinal positions, which are offsets to identify where fields are within…

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October 3, 2016

Netezza

Netezza Best Practices to Improve Performance

Today there is a increased demand in advanced analytics on big data. Netezza is designed with built in functionalities to perform advanced analytics on really big data sets. To improve the performance, you should follow some Netezza best practices. Best practice should not mean hundreds of rules and regulations to follow. Recommended that basic principles are followed on following features of Netezza: Distribution Data types Statistics Zone maps Clustered base tables Groom table command Netezza Best Practices on Distributions In a Netezza data warehouse appliance good distribution is fundamental element…

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October 2, 2016

Netezza

Netezza Cross Database Access and its Restrictions

Netezza cross database access does allows you to execute the objects such as tables, view, synonyms that are available on the same Netezza server. You can can INSERT, UPDATE or DELETE data from current database by referring objects in other database on same server. For example, TRAINING1.ADMIN(ADMIN)=>SELECT * FROM TRAINING1..TEST1; Read: Access Netezza Database, Tools and Examples Netezza nzsql Command and its Usage Netezza Synonym Best Practices and Examples Referencing Database Object from other Database To access objects in other databases on the same Netezza system, you must use three-level…

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September 28, 2016

Netezza

Netezza Advanced Date Functions and Examples

Netezza Advanced Date Functions are available in Netezza SQL extensions tool kit. You have to download it from IBM fix central and install it in required database. You cannot access these functions otherwise. Read: how to download and Install Netezza SQL extensions toolkit These advanced functions are different than standard Netezza data time functions. You can read about the standard Netezza date functions from below post: Netezza Data Functions and Examples You may want to read: nzsql command and its Usage Netezza Analytics Functions and Examples IBM Netezza Conversion Functions…

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September 24, 2016