通过 Java 从 Postgresql 获取返回值
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Get RETURNING value from Postgresql via Java
提问by Jeff
From Java, I'm calling a prepared statement in Postgresql with an insert that has a RETURNING clause for my identity column. In PG admin it comes right back, but not sure how to get it from my prepared statement:
在 Java 中，我在 Postgresql 中调用了一个准备好的语句，其中插入了一个为我的标识列提供 RETURNING 子句的插入语句。在 PG admin 中它会立即返回，但不确定如何从我准备好的语句中获取它：
String insertStatement = "INSERT INTO person(\n" +
" name, address, phone, customer_type, \n" +
" start_dtm)\n" +
" VALUES (?, ?, ?, ?, \n" +
" ?)\n" +
" RETURNING person_id;";
PreparedStatement stmt = connection.prepareStatement(insertStatement);
stmt.setObject(1, perToSave.getName(null));
stmt.setObject(2, editToSave.getAddress());
stmt.setObject(3, editToSave.getPhone());
stmt.setObject(4, editToSave.getCustType());
long epochTime = java.lang.System.currentTimeMillis();
stmt.setObject(5, new java.sql.Date(epochTime));
stmt.executeUpdate();
采纳答案by hd1
According to the javadoc, PreparedStatement inherits from Statementand the latter contains a getResultSet() method. In other words, try this:
根据javadoc， PreparedStatement 继承自Statement，后者包含一个 getResultSet() 方法。换句话说，试试这个：
String insertStatement = "INSERT INTO person(\n" +
" name, address, phone, customer_type, \n" +
" start_dtm)\n" +
" VALUES (?, ?, ?, ?, \n" +
" ?)\n" +
" RETURNING person_id;";
PreparedStatement stmt = connection.prepareStatement(insertStatement);
stmt.setObject(1, perToSave.getName(null));
stmt.setObject(2, editToSave.getAddress());
stmt.setObject(3, editToSave.getPhone());
stmt.setObject(4, editToSave.getCustType());
long epochTime = java.lang.System.currentTimeMillis();
stmt.setObject(5, new java.sql.Date(epochTime));
stmt.executeUpdate();
ResultSet last_updated_person = stmt.getResultSet();
last_updated_person.next();
int last_updated_person_id = last_updated_person.getInt(1);
Leave a comment if you have further issues.
如果您有其他问题，请发表评论。
回答by cardamo
Calling executeUpdate()expects no result from statement. Call stmt.execute() and then stmt.getResultSet()
调用不executeUpdate()希望语句产生任何结果。调用 stmt.execute() 然后调用 stmt.getResultSet()
回答by Malba
I do not have enough reputation to Comment and my Edit got rejected, so sorry for re-posting the already accepted answer from hd1.
我没有足够的声誉来发表评论，我的编辑被拒绝了，很抱歉重新发布hd1已经接受的答案。
executeUpdate expects no returns; use execute. Check if there is some results before trying to retrieve the value.
executeUpdate 不期望返回；使用执行。在尝试检索值之前检查是否有一些结果。
String insertStatement = "INSERT INTO person(\n" +
" name, address, phone, customer_type, \n" +
" start_dtm)\n" +
" VALUES (?, ?, ?, ?, \n" +
" ?)\n" +
" RETURNING person_id;";
PreparedStatement stmt = connection.prepareStatement(insertStatement);
stmt.setObject(1, perToSave.getName(null));
stmt.setObject(2, editToSave.getAddress());
stmt.setObject(3, editToSave.getPhone());
stmt.setObject(4, editToSave.getCustType());
long epochTime = java.lang.System.currentTimeMillis();
stmt.setObject(5, new java.sql.Date(epochTime));
stmt.execute();
ResultSet last_updated_person = stmt.getResultSet();
if(last_updated_person.next()) {
int last_updated_person_id = last_updated_person.getInt(1);
}
