# Patterns

Available in...

* Big Data Platform
* Cloud API Services Platform
* Cloud Big Data Platform
* Cloud Data Fabric
* Cloud Data Management Platform
* Data Fabric
* Data Management Platform
* Data Services Platform
* Qlik Talend Cloud Enterprise Edition
* Qlik Talend Cloud Premium Edition
* Real-Time Big Data Platform

Patterns are sets of strings against which you can match the content of the columns to be analyzed.

## Pattern types

Two types of patterns are listed under the Patterns folder in the DQ repository tree view: regular expressions and SQL patterns.

Regular expressions (regex) are predefined patterns that you can use to search and manipulate text in the databases to which you connect. You can also create your own regular expressions and use them to analyze columns.

When selecting a pattern in a Job, the regular expression for the current database type is used:

* If the regular expression does not exist for this database type, the default regular expression in the selected pattern is used.
* If you remove the regular expression for this database type in a pattern that is used in Jobs, the Jobs are updated with the default regular expression in the selected pattern.

SQL patterns are a kind of personalized patterns that are used in SQL queries. These patterns usually contain the percent sign (%). For more information on SQL wildcards, see [SQL Wildcard](https://www.w3schools.com/SQL/sql_wildcards.asp).

You can use any of the above two pattern types either with column analyses or with the analyses of a set of columns (simple table analyses). These pattern-based analyses illustrate the frequencies of various data patterns found in the values of the analyzed columns. For more information, see [Creating a basic analysis on a database column](https://help.qlik.com/talend/en-US/studio-user-guide/8.0/creating-basic-analysis-on-database-column) and [Creating an analysis of a set of columns using patterns](https://help.qlik.com/talend/en-US/studio-user-guide/8.0/creating-analysis-of-set-of-columns-using-patterns).

From Talend Studio, you can generate graphs to represent the results of analyses using patterns. You can also view tables in the analysis results that write in words the generated graphs. From those graphs and analysis results you can easily determine the percentage of invalid values based on the listed patterns.

Management processes for SQL patterns and regular expressions, including those for Java, are the same. For more information, see [Managing regular expressions and SQL patterns](https://help.qlik.com/talend/en-US/studio-user-guide/8.0/managing-regular-expressions-and-sql-patterns).

Information noteNote: Some databases do not support regular expressions. To work with such databases, some configuration is necessary before being able to use regular expressions. For more information, see [Managing User-Defined Functions in databases](https://help.qlik.com/talend/en-US/studio-user-guide/8.0/managing-user-defined-functions-in-databases).

The following table shows the patterns that you can select in any database:

| Indicator | Supported data types with the Java analysis engine | Supported data types with the SQL analysis engine |
| --- | --- | --- |
| SQL Patterns | None | All data types |
| Regex Patterns | All data types | All data types |

### In this section

* [Managing User-Defined Functions in databases](https://help.qlik.com/talend/en-US/studio-user-guide/8.0-R2026-09/managing-user-defined-functions-in-databases)
* [Adding regular expressions and SQL patterns to column analyses](https://help.qlik.com/talend/en-US/studio-user-guide/8.0-R2026-09/adding-regular-expressions-and-sql-patterns-to-column-analyses)
* [Generating a Job to recuperate regular expressions](https://help.qlik.com/talend/en-US/studio-user-guide/8.0-R2026-09/generating-job-to-recuperate-regular-expressions)
* [Managing regular expressions and SQL patterns](https://help.qlik.com/talend/en-US/studio-user-guide/8.0-R2026-09/managing-regular-expressions-and-sql-patterns)