Question

我似乎无法在准备好的声明中设置正确的类型。这段代码：

String sql = "delete from foo where ctid = ?";
PreparedStatement deleteStmt = conn.prepareStatement( sql );
deleteStmt.setString(1, "(0,43)");  // select ctid from foo shows (0,43) exists....
int a = deleteStmt.executeUpdate();

抛出此异常：

org.postgresql.util.PSQLException: ERROR: operator does not exist: tid = character varying
Hint: No operator matches the given name and argument type(s). You might need to add explicit type casts.   Position: 28

请注意，从psql中，删除使用字符串：

mydb=# DELETE FROM foo where ctid = '(0,43)';
DELETE 1

JDBC PreparedStatement中tid的正确类型/编码是什么？我试过setRowId（）（抛出ava.sql.SQLFeatureNotSupportedException：方法org.postgresql.jdbc4.Jdbc4PreparedStatement.setRowId（int，RowId）尚未实现。）和setBytes（）（throws ...运算符不存在：tid = byte）

Answer 1

解决！您必须手动创建PGO对象并设置类型和值，并将其作为对象传递给JDBC。这现在有效：

sql = "delete from foo where ctid = ?";
deleteStmt = conn.prepareStatement( sql );
org.postgresql.util.PGobject pgo = new org.postgresql.util.PGobject();
pgo.setType("tid");
pgo.setValue("(0,54)");  // value is a string as might be returned in select ctid from foo and then resultSet.getString(1);
deleteStmt.setObject(1, pgo);

int a = deleteStmt.executeUpdate();
System.out.println("delete returns " + a);

Answer 2

旧话题，但我想补充一点写作

where ctid = ?::tid";

而不是

where ctid = ?::ctid";

做了这个伎俩。然后可以使用PreparedStatement.setString（x，＆＃34;（10,3）＆＃34;）

postgres中ctid的JDBC类型是什么？

2 个答案: