Question

什么是PLSQL（Oracle）等效于此SQL服务器代码段？

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，并让JDBC获取新ID的副本？

修改 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()（例如，参见this answer），但这仍然是Oracle JDBC驱动程序不支持的。

您最好的选择是使用CallableStatement 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);
    // ...

在同一交易中SELECT sequencename.CURRVAL之后

或开火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returning子句。

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

查看this link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。

Answer 3

您可以使用getGeneratedKeys（），明确选择关键字段。这是一个片段：

    // change the string to your connection string
    Connection connection = DriverManager.getConnection("connection string");

    // assume that the field "id" is PK, and PK-trigger exists 
    String sql = "insert into my_table(id) values (default)";
    // you can select key field by field index
    int[] colIdxes = { 1 };
    // or by field name
    String[] colNames = { "id" };

    // Java 1.7 syntax; try-finally for older versions
    try (PreparedStatement preparedStatement = connection.prepareStatement(sql, colNames))
    {
        // note: oracle JDBC driver do not support auto-generated key feature with batch update
        //          // insert 5 rows
        //          for (int i = 0; i < 5; i++)
        //          {
        //              preparedStatement.addBatch();
        //          }
        //          
        //          int[] batch = preparedStatement.executeBatch();
        preparedStatement.executeUpdate();

        // get generated keys
        try (ResultSet resultSet = preparedStatement.getGeneratedKeys())
        {
            while (resultSet.next())
            {
                // assume that the key's type is BIGINT
                long id = resultSet.getLong(1);
                assertTrue(id != 0);

                System.out.println(id);
            }
        }
    }

参考详情：http://docs.oracle.com/cd/E16655_01/java.121/e17657/jdbcvers.htm#CHDEGDHJ

Answer 4

如果将spring-jdbc用于数据库，则可以考虑使用morejdbc中的整洁包装器，它看起来像这样：

import static org.morejdbc.SqlTypes.BIGINT;
import static org.morejdbc.JdbcCall.callSql;
import static org.morejdbc.*;
...

Out<Long> idOut = Out.of(BIGINT);
jdbcTemplate.execute(callSql("BEGIN INSERT INTO mytable(id, content) VALUES (seq_mytable.NEXTVAL(), ?) "
        + "RETURNING id INTO ?; END;")
        .in(content)
        .out(BIGINT, idOut));
System.out.println("Id is " + idOut.get());

如果您喜欢pojo

@lombok.Data
public class Entity {
    private long id;
    private String content;
}

它可能更简洁：

Entity entity = ;

jdbcTemplate.execute(callSql("BEGIN INSERT INTO mytable(id, content) VALUES (seq_mytable.NEXTVAL(), ?) "
        + "RETURNING id INTO ?; END;")
        .in(entity.getContent())
        .out(BIGINT, entity::setId));
System.out.println("Id is " + entity.get());

PLSQL JDBC：如何获取最后一行ID？

4 个答案: