Netezza

Netezza Delete Join Syntax – Deleting Referring other Table

Every application requires the data, data storage is very much important. In the digital world, we use databases (in-fact tables) to store information. Data is collected over the time and it may or may not be accurate. In some cases, you may want to delete data from the table based on the data available in other table over same or other database on same Netezza server. You cannot access the table stored on other Netezza server. In this article, we have explained the Netezza delete join syntax and example on…

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February 16, 2017
Netezza

Netezza Update Join Syntax – Update using other Table

Every application that require the data; data storage is very much important. In the digital world, we use databases (in fact tables) to store information. Data is collected over the time and it may or may not be accurate. In some cases you may want to update the table based on the data available in other table over same or other database on same server. In this article, we have explained the Netezza Update Join Syntax and example on how to update using Data in other Table. Read: How Netezza…

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February 9, 2017
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