Oracle 序列创建了两次。 ORA-00955: 名称已被现有对象使用
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【中文标题】Oracle 序列创建了两次。 ORA-00955: 名称已被现有对象使用【英文标题】：Oracle sequence created twice. ORA-00955: name is already used by an existing object 【发布时间】：2015-05-22 12:29:53 【问题描述】：编辑根据您的建议，代码和错误。我现在收到错误“ORA-00955：名称已被现有对象使用”。每次调用 DataStoreManager 构造函数时，序列创建都会产生此错误。
现在是代码：
public class DataStoreManager
private Connection connection;
private PreparedStatement lookForAccount;
private PreparedStatement addAccount;
private PreparedStatement updaterBalance;
private PreparedStatement reachOperation;
public DataStoreManager(String url, String user, String password) throws DataStoreException, SQLException
try
connection = DriverManager.getConnection(url,user,password);
connection.setAutoCommit(false);
this.createDB();
lookForAccount = connection.prepareStatement("SELECT * FROM accounts WHERE account_id = ?");
addAccount = connection.prepareStatement("INSERT INTO accounts (account_id, balance) VALUES (? , 0.0)");
updaterBalance = connection.prepareStatement("UPDATE accounts SET balance = ? WHERE account_id = ?");
reachOperation = connection.prepareStatement("SELECT * FROM operations WHERE account_id = ? AND (date BETWEEN ? AND ?)");
catch (SQLException error)
error.printStackTrace();
throw error;
public void createDB() throws DataStoreException
try
Statement statmnt = connection.createStatement();
statmnt.executeUpdate("DROP TABLE operations");
statmnt.executeUpdate("DROP TABLE accounts");
statmnt.executeUpdate("CREATE TABLE accounts ( account_id INTEGER, balance DOUBLE PRECISION)");
statmnt.executeUpdate("CREATE TABLE operations ( operation_id INTEGER, account_id INTEGER, amount DOUBLE PRECISION, mydate DATE NOT NULL)");
//implement primary Key constraint.
statmnt.executeUpdate("ALTER TABLE accounts ADD CONSTRAINT accounts_PK PRIMARY KEY ( account_id )");
//implement foreign Key constraint
statmnt.executeUpdate("ALTER TABLE operations ADD CONSTRAINT accountID FOREIGN KEY ( account_id )"
+ "REFERENCES accounts ( account_id )");
// implement sequence for auto implement.
statmnt.executeUpdate("CREATE SEQUENCE operationID MINVALUE 1 START WITH 1 INCREMENT BY 1 CACHE 10");
statmnt.executeUpdate("CREATE SEQUENCE logID MINVALUE 1 START WITH 1 INCREMENT BY 1 CACHE 10");
// implement balance always positive constraint
statmnt.executeUpdate("ALTER TABLE accounts ADD CONSTRAINT balance_must_be_positive CHECK (balance >= 0)");
// Auto operation.
statmnt.executeUpdate("CREATE TRIGGER addingOrder BEFORE UPDATE ON accounts FOR EACH ROW BEGIN"
+ " INSERT INTO operations(operation_id, account_id, amount, mydate) "
+ " VALUES (operationID.nextval, :OLD.account_id, :NEW.amount - :OLD.amount, SYSDATE) END");
connection.commit();
catch (Exception error)
error.printStackTrace();
public boolean createAccount(int number) throws DataStoreException, SQLException
try
lookForAccount.setInt(1, number);
Boolean result = lookForAccount.execute();
if(result == true)
addAccount.setInt(1, number);
addAccount.executeUpdate();
connection.commit();
return true;
else
return false;
catch (SQLException error)
error.printStackTrace();
throw error;
这是我的错误：
java.sql.SQLException: ORA-00955: name is already used by an existing object
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
at oracle.jdbc.ttc7.Oall7.receive(Oall7.java:590)
at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1973)
at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteFetch(TTC7Protocol.java:1119)
at oracle.jdbc.driver.OracleStatement.executeNonQuery(OracleStatement.java:2191)
at oracle.jdbc.driver.OracleStatement.doExecuteOther(OracleStatement.java:2064)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2989)
at oracle.jdbc.driver.OracleStatement.executeUpdate(OracleStatement.java:891)
at services.DataStoreManager.createDB(DataStoreManager.java:105)
at services.DataStoreManager.<init>(DataStoreManager.java:55)
at application.SimpleTest.main(SimpleTest.java:145)
Running single-user tests...
Running multi-users tests...
java.sql.SQLException: ORA-00955: name is already used by an existing object
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
at oracle.jdbc.ttc7.Oall7.receive(Oall7.java:590)
at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1973)
at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteFetch(TTC7Protocol.java:1119)
at oracle.jdbc.driver.OracleStatement.executeNonQuery(OracleStatement.java:2191)
at oracle.jdbc.driver.OracleStatement.doExecuteOther(OracleStatement.java:2064)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2989)
at oracle.jdbc.driver.OracleStatement.executeUpdate(OracleStatement.java:891)
at services.DataStoreManager.createDB(DataStoreManager.java:105)
at services.DataStoreManager.<init>(DataStoreManager.java:55)
at application.SimpleTest.main(SimpleTest.java:160)
user#0[services.DataStoreManager@e00c09]: starting
user#0[services.DataStoreManager@e00c09]: exiting
java.sql.SQLException: ORA-00955: name is already used by an existing object
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
at oracle.jdbc.ttc7.Oall7.receive(Oall7.java:590)
at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1973)
at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteFetch(TTC7Protocol.java:1119)
at oracle.jdbc.driver.OracleStatement.executeNonQuery(OracleStatement.java:2191)
at oracle.jdbc.driver.OracleStatement.doExecuteOther(OracleStatement.java:2064)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2989)
at oracle.jdbc.driver.OracleStatement.executeUpdate(OracleStatement.java:891)
at services.DataStoreManager.createDB(DataStoreManager.java:105)
at services.DataStoreManager.<init>(DataStoreManager.java:55)
at application.SimpleTest.main(SimpleTest.java:160)
user#1[services.DataStoreManager@111f9b]: starting
user#1[services.DataStoreManager@111f9b]: exiting
java.sql.SQLException: ORA-00955: name is already used by an existing object
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)user#2[services.DataStoreManager@1363271]: starting
user#2[services.DataStoreManager@1363271]: exiting
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
at oracle.jdbc.ttc7.Oall7.receive(Oall7.java:590)
at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1973)
at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteFetch(TTC7Protocol.java:1119)
at oracle.jdbc.driver.OracleStatement.executeNonQuery(OracleStatement.java:2191)
at oracle.jdbc.driver.OracleStatement.doExecuteOther(OracleStatement.java:2064)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2989)
at oracle.jdbc.driver.OracleStatement.executeUpdate(OracleStatement.java:891)
at services.DataStoreManager.createDB(DataStoreManager.java:105)
at services.DataStoreManager.<init>(DataStoreManager.java:55)
at application.SimpleTest.main(SimpleTest.java:160)
java.sql.SQLException: ORA-00955: name is already used by an existing object
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
at oracle.jdbc.ttc7.Oall7.receive(Oall7.java:590)
at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1973)
at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteFetch(TTC7Protocol.java:1119)
at oracle.jdbc.driver.OracleStatement.executeNonQuery(OracleStatement.java:2191)
at oracle.jdbc.driver.OracleStatement.doExecuteOther(OracleStatement.java:2064)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2989)
at oracle.jdbc.driver.OracleStatement.executeUpdate(OracleStatement.java:891)
at services.DataStoreManager.createDB(DataStoreManager.java:105)
at services.DataStoreManager.<init>(DataStoreManager.java:55)
at application.SimpleTest.main(SimpleTest.java:160)
user#3[services.DataStoreManager@114f313]: starting
user#3[services.DataStoreManager@114f313]: exiting
java.sql.SQLException: ORA-00955: name is already used by an existing object
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)user#4[services.DataStoreManager@d767dc]: starting
user#4[services.DataStoreManager@d767dc]: exiting
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
at oracle.jdbc.ttc7.Oall7.receive(Oall7.java:590)
at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1973)
at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteFetch(TTC7Protocol.java:1119)
at oracle.jdbc.driver.OracleStatement.executeNonQuery(OracleStatement.java:2191)
at oracle.jdbc.driver.OracleStatement.doExecuteOther(OracleStatement.java:2064)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2989)
at oracle.jdbc.driver.OracleStatement.executeUpdate(OracleStatement.java:891)
at services.DataStoreManager.createDB(DataStoreManager.java:105)
at services.DataStoreManager.<init>(DataStoreManager.java:55)
at application.SimpleTest.main(SimpleTest.java:160)
【问题讨论】：
什么时候调用 createDB()？你确定你连接到同一个数据源吗？同一个用户？如果您的表不在同一个架构中，您可能会丢失同义词。 啊，你是对的，我忘了在构造函数中调用createDB。我添加了它，但我得到了同样的错误：S 我真的不知道如何查看我是否在同一个数据源或架构上（我使用同一个用户登录 sqlplus 并在连接方法中） 请编辑您的问题以显示现在的代码。同时显示堆栈跟踪。 可能不相关，但尽管如此：不要将executeQuery() 用于 DDL 语句。使用execute() 或executeUpdate()
@Mark Leiber：我编辑了。
【参考方案1】：
如果您的任何 SQL 语句产生错误（例如，如果表不存在而您尝试删除它），您的 createDB() 方法将出现问题。此时，您的代码将跳转到catch 块，并且不会创建任何数据库对象。您需要将每个 DROP 语句包装在 try/catch 块中，以便可以捕获和处理任何错误（或者在您的情况下可能可以安全地忽略），然后 CREATE 语句将运行。
您也只为您的表运行DROP 语句。您需要对序列和触发器执行相同操作。
您的触发器也无效。帐户表只有 account_id 和 balance 的列。您不能为操作表中的列引用 :old 或 :new 值。所以:old.amount 和:new.amount 无效，:old.account_id 是accounts 表中的account_id（结果与operations 表中的account_id 相同，因为它是外键）。您还缺少两个分号。它应该是这样的：
statmnt.executeUpdate("CREATE TRIGGER addingOrder BEFORE UPDATE ON accounts FOR EACH ROW BEGIN"
+ " INSERT INTO operations(... columns ...) "
+ " VALUES (... values ...); END;");
按照您对事物进行编码的方式，您首先尝试通过DROPPING 进行一些清理，然后是CREATE 的所有内容。测试完成后，您将保留所有数据库对象。我建议您颠倒您的顺序，以便在测试开始时创建您的对象，然后在您 DROP 的最后进行拆解，以便您的数据库保持干净。
【讨论】：
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