CREATE FUNCTION
June 27, 2018 ยท View on GitHub
CREATE FUNCTION udf_name AS qualified_class_name RETURNS data_type USING JAR '/path/to/file/udf.jar'
Description
Creates a function. Users can define a function and completely customize how SnappyData evaluates data and manipulates queries using UDF and UDAF functions across sessions. The definition of the functions is stored in a persistent catalog, which enables it to be used after node restart as well.
You can extend any one of the interfaces in the package org.apache.spark.sql.api.java. These interfaces can be included in your client application by adding snappy-spark-sql_2.11-2.0.3-2.jar to your classpath.
!!! Note
For input/output types:
The framework always returns the Java types to the UDFs. So, if you are writing scala.math.BigDecimal as an input type or output type, an exception is reported. You can use java.math.BigDecimal in the SCALA code.
Return Types to UDF Program Type Mapping
| SnappyData Type | UDF Type |
|---|---|
| STRING | java.lang.String |
| INTEGER | java.lang.Integer |
| LONG | java.lang.Long |
| DOUBLE | java.lang.Double |
| DECIMAL | java.math.BigDecimal |
| DATE | java.sql.Date |
| TIMESTAMP | java.sql.Timestamp |
| FLOAT | java.lang.Float |
| BOOLEAN | java.lang.Boolean |
| SHORT | java.lang.Short |
| BYTE | java.lang.Byte |
| CHAR | java.lang.String |
| VARCHAR | java.lang.String |
Example
CREATE FUNCTION APP.strnglen AS some.package.StringLengthUDF RETURNS Integer USING JAR '/path/to/file/udf.jar'
You can write a JAVA or SCALA class to write an UDF implementation.
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