PreparedStatement,using one parameter for multiple “?”

Question

I have a insert if not exists query as below.

BEGIN
    IF NOT EXISTS (SELECT * FROM tbl_sampleTable WHERE name = ? or subject = ?)
    BEGIN
        INSERT INTO tbl_sampleTable VALUES (?,?)
    END
END

I am executing the above query with JDBC PreparedStatement as below

    pst.setString(1, name);
    pst.setString(2, subject);
    pst.setString(3, subject);
    pst.setString(4, name);
    pst.executeUpdate();

I am getting these name and subject as method parameters, is there anyway i can provide values for multiple "?" with same parameter as they are same, instead of mentioning them two times each.

Edit: I don't use spring or any other framework, if it is relevant.

Answer 1

JDBC doesn't support named parameters, but Spring JDBC provides this functionality with NamedParameterJdbcTemplate

Answer 2

Just in this case you might use SQL variables. It is not a general solution. And also many SQL vendor specific variants know such insert-when-not-exists constructs, not needing such archaic code.

BEGIN
    DECLARE @MyName varchar(100);
    DECLARE @MySubject varchar(100);
    SET @MyName = ?;
    SET @MySubject = ?;
    IF NOT EXISTS (SELECT * FROM tbl_sampleTable WHERE name = @MyName OR subject = @MySubject)
    BEGIN
        INSERT INTO tbl_sampleTable(subject, name) VALUES (@MySubject, @MyName)
    END
END

Answer 3

You need to add some wrapper, without using Spring (NamedParameterJdbcTemplate) you can try other as HTTP-RPC framework

The org.httprpc.sql.Parameters class provided by the HTTP-RPC framework brings named parameter support to JDBC. The parse() method of this class is used to create a Parameters instance from a JPA-like SQL query; for example:

SELECT * FROM user WHERE first_name LIKE :pattern or last_name LIKE :pattern

It takes a string or reader containing the query text as an argument:

 Parameters parameters = Parameters.parse(sqlReader);

The getSQL() method of the Parameters class returns the processed query in standard JDBC syntax. This value can be used in a call to Connection#prepareStatement():

PreparedStatement statement = connection.prepareStatement(parameters.getSQL());

Parameter values are specified via the put() method:

parameters.put("pattern", pattern);

The values are applied to the statement via the apply() method:

parameters.apply(statement);

Answer 4

Usefull trick in this situation is to declare variables.

You bind the values to the variables only once and you can use them several times in your PL/SQL block.

DECLARE
  l_name tbl_sampleTable.name%TYPE := ?;
  l_subject tbl_sampleTable.subject%TYPE := ?;
BEGIN
    IF NOT EXISTS (SELECT * FROM tbl_sampleTable WHERE name = l_name  or subject = l_subject )
    BEGIN
        INSERT INTO tbl_sampleTable (name,subject)
        VALUES (l_name ,l_subject )
    END
END