PLSQL JDBC:如何获取最后一行ID？

Question

什么是PLSQL(Oracle)相当于这个SQL服务器片段？

BEGIN TRAN
INSERT INTO mytable(content) VALUES ("test") -- assume there's an ID column that is autoincrement
SELECT @@IDENTITY
COMMIT TRAN

在C#中,您可以调用myCommand.ExecuteScalar()来检索新行的ID.

如何在Oracle中插入新行,让JDBC获取新ID的副本？

编辑: BalusC提供了一个非常好的起点.由于某种原因,JDBC不喜欢命名参数绑定.这给出了"错误设置或注册的参数"SQLException.为什么会这样？

        OracleConnection conn = getAppConnection();
        String q = "BEGIN INSERT INTO tb (id) values (claim_seq.nextval) returning id into :newId; end;" ;
        CallableStatement cs = (OracleCallableStatement) conn.prepareCall(q);
        cs.registerOutParameter("newId", OracleTypes.NUMBER);
        cs.execute();
        int newId = cs.getInt("newId");

Answer 1

通常你可以使用Statement#getGeneratedKeys()它(参见这个例子的答案),但这仍然是(仍然)不支持Oracle JDBC驱动程序.

最好的办法是要么使使用CallableStatement了RETURNING条款:

String sql = "BEGIN INSERT INTO mytable(id, content) VALUES (seq_mytable.NEXTVAL(), ?) RETURNING id INTO ?; END;";

Connection connection = null;
CallableStatement statement = null;

try {
    connection = database.getConnection();
    statement = connection.prepareCall(sql);
    statement.setString(1, "test");
    statement.registerOutParameter(2, Types.NUMERIC);
    statement.execute();
    int id = statement.getInt(2);
    // ...

或者在同一笔交易SELECT sequencename.CURRVAL之后开火INSERT:

String sql_insert = "INSERT INTO mytable(content) VALUES (?)";
String sql_currval = "SELECT seq_mytable.CURRVAL FROM dual";

Connection connection = null;
PreparedStatement statement = null;
Statement currvalStatement = null;
ResultSet currvalResultSet = null;

try {
    connection = database.getConnection();
    connection.setAutoCommit(false);
    statement = connection.prepareStatement(sql_insert);
    statement.setString(1, "test");
    statement.executeUpdate();
    currvalStatement = connection.createStatement();
    currvalResultSet = currvalStatement.executeQuery(sql_currval);
    if (currvalResultSet.next()) {
        int id = currvalResultSet.getInt(1);
    }
    connection.commit();
    // ...

Answer 2

您可以使用Oracle的return子句.

insert into mytable(content) values ('test') returning your_id into :var;

查看此链接以获取代码示例.您需要Oracle 10g或更高版本以及新版本的JDBC驱动程序.