java - PLSQL JDBC : How to get last row ID?

Question

此 SQL 服务器代码段的 PLSQL (Oracle) 等效项是什么？

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，并让 JDBC 获取新 ID 的副本？

编辑:BalusC 提供了一个很好的起点。出于某种原因，JDBC 不喜欢命名参数绑定(bind)。这会产生“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

通常您会使用 Statement#getGeneratedKeys()为此(另请参阅 this answer 的示例)，但到目前为止(仍然)不受 Oracle JDBC 驱动程序支持。

你最好的选择是要么利用CallableStatement使用 RETURNING 子句:

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);
    // ...

或者在同一事务中的INSERT 之后触发SELECT sequencename.CURRVAL:

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();
    // ...