In my other Redshift related article, we have discussed how to define a primary key, foreign key and NOT NULL constraint. In this article, we will check how to use Redshift UNIQUE KEY constraint with its syntax. Redshift Unique Key Constraint Amazon AWS Redshift is an analytical columnar database. Many transactional database features are not supported on Redshift. You can define a unique key, but Unique key is informational only; They are not enforced by Amazon Redshift. The Amazon data warehouse appliance supports referential integrity constraints such as Redshift primary…

Amazon Redshift is one of the earliest cloud data warehouses. It is based on the PostgreSQL. There are many features that are common in Redshift and PostgreSQL. Amazon Redshift provides many features to the user who wants to migrate to AWS Redshift. One of such features is primary key constraints. Basically, Redshift supports the referential integrity constraint such as primary key, foreign key, not null and unique key. You can create a primary key during table creation, that is, table DDL or you can use alter table command to add…

The relational databases such as Teradata and Oracle supports the multiple columns in WHERE clause. It is one of the main requirements when you are migrating from legacy databases such as Teradata to Amazon Redshift. In this article, we will check Redshift WHERE clause multiple columns support. What is a WHERE Clause? The WHERE clause contains conditions that either apply predicates to columns in tables or join multiple tables. Almost all modern databases allow you to join tables in WHERE clause. The WHERE clause specifies a condition that matches a subset of…

Like many other cloud data warehouses, Amazon Redshift supports set operators such as UNION, EXCEPT/MINUS and INTERSECT to combine two or more similar data sets from two or more SELECT statements. Here the similar data set literally mean, the data type of the result set should also match, otherwise you have to explicitly type cast data when using Redshift set operators. Set Operators in Redshift Types of Set Operators in Redshift Amazon Redshift supports the following types of set operators: UNION [DISTINCT] and UNION ALLINTERSECT [DISTINCT]EXCEPT [DISTINCT] or MINUS [DISTINCT]…