CallableStatements and INOUT parameters

INOUT parameters map to an array of the parameter type in the Java programming language. (The method must take an array as its parameter.) This conforms to the recommendations of the SQL standard.

Given the following example:

CallableStatement call = conn.prepareCall(
    "{CALL doubleMyInt(?)}");
// for inout parameters, it is good practice to
// register the outparameter before setting the input value
call.registerOutParameter(1, Types.INTEGER);
call.setInt(1,10);
call.execute();
int retval = call.getInt(1);

The method doubleIt should take a one-dimensional array of ints. Here is sample source code for that method:

public static void doubleMyInt(int[] i) {
    i[0] *=2;
    /* Derby  returns the first element of the array.*/
}

Note: The return value is not wrapped in an array even though the parameter to the method is.

The following table shows the parameter array types and return types that correspond to JDBC types.

Table 1. INOUT parameter type correspondence
JDBC Type	Array Type for Method Parameter	Value and Return Type
BIGINT	long[]	long
BINARY	byte[][]	byte[]
BLOB	java.sql.Blob[]	java.sql.Blob
BOOLEAN	boolean[]	boolean
CLOB	java.sql.Clob[]	java.sql.Clob
DATE	java.sql.Date[]	java.sql.Date
DOUBLE	double[]	double
FLOAT	double[]	double
INTEGER	int[]	int
LONGVARBINARY	byte[][]	byte[]
REAL	float[]	float
SMALLINT	short[]	short
TIME	java.sql.Time[]	java.sql.Time
TIMESTAMP	java.sql.Timestamp[]	java.sql.Timestamp
VARBINARY	byte[][]	byte[]
OTHER	yourType[]	yourType
JAVA_OBJECT	yourType[]	yourType

Register the output type of the parameter before executing the call. For INOUT parameters, it is good practice to register the output parameter before setting its input value.