The following query is correct in Oracle 12c:
SELECT *
FROM dual
MATCH_RECOGNIZE (
MEASURES a.dummy AS dummy
PATTERN (a?)
DEFINE a AS (1 = 1)
)
But it doesn't work through JDBC because of the ?
character that is used as a regular expression character, not as a bind variable.
What's the correct way to escape the ?
through JDBC, assuming I want to run this as a PreparedStatement
with bind variables?
Q 5 - Which of the following is correct about PreparedStatement? A - PreparedStatement allows mapping different requests with same prepared statement but different arguments to execute the same execution plan.
You must supply values for every parameter before executing the SQL statement. The setXXX() methods bind values to the parameters, where XXX represents the Java data type of the value you wish to bind to the input parameter.
The PreparedStatement interface extends the Statement interface it represents a precompiled SQL statement which can be executed multiple times. This accepts parameterized SQL quires and you can pass 0 or more parameters to this query.
1. PreparedStatement in Java allows you to write a parameterized query that gives better performance than the Statement class in Java. 2. In the case of PreparedStatement, the Database uses an already compiled and defined access plan, this allows the prepared statement query to run faster than a normal query.
This is covered explicitly in the documentation:
MATCH_RECOGNIZE
ClauseThe
?
character is used as a token inMATCH_RECOGNIZE
clause in Oracle Database 11g and later versions. As the JDBC standard defines the?
character as a parameter marker, the JDBC Driver and the Server SQL Engine cannot distinguish between different uses of the same token.In earlier versions of JDBC Driver, if you want to interpret the
?
character as aMATCH_RECOGNIZE
token and not as a parameter marker, then you must use aStatement
instead of aPreparedStatement
and disable escape processing. However, starting from Oracle Database 12c Release 1 (12.1.0.2), you can use the'{\ ... \}'
syntax while using the?
character, so that the JDBC driver does not process it as a parameter marker and allows the SQL engine to process it.
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