Creating a Query¶
A Query is a request for specific data, executed through commands such as SQL statements, which enables the manipulation of data with Integrated Data Lake. Each time a Query is created, an associated job is automatically generated. For more information on jobs, refer File Ingestion Jobs or Query execution jobs.
To perform SQL-like operations, Data Contextualization makes use of the spark.sql module.
The following types of Queries are supported:
Physical Query: The Query created using schemas and its properties present in registry is called a physical Query. The user is allowed to form a valid SQL statement using schema and its properties.
Business Query: The Query created using classes and its properties present in ontology is called a business Query. The user is allowed to form a valid SQL statement using class or classes and its properties. Business Queries use the underlying mappings provided in the semantic models to Query data from multiple sources of data.
Queries (both physical and business) in Data Contextualization can be Static or Dynamic in type.
Static Query: A Static Query contains parameters of which the value of parameters are defined at the time of creation. The value of any parameter cannot be modified at the time of execution.
Dynamic Query: A Dynamic Query contains parameters of which value can provided at the time of execution for column names in the selected clause. Dynamic queries help users to create multiple execution requests on a single Query.
For more information on Queries, refer Creating Native SQL based query.
To create a Query, follow these steps:
- From the left navigation, click "Queries" and then click "Create Query".
- Select the Query type.
- Enter the general details and SQL Statement.
- Enable the toggle option to select Dynamic Query, otherwise Static Query is used by default.
- Click "Confirm".
A Query is successfully created.
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