[英]what did I do wrong with java and sql database?
我正在嘗試使用jdbc:derby數據庫創建一個表。
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
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public class DBCONNECT {
Connection con;
public DBCONNECT()
{
connect();
}
private void connect()
{
try {
con= DriverManager.getConnection("jdbc:derby:relative/db/dubbydata.db;create=true;","APP","");
PreparedStatement st= con.prepareStatement("SELECT * FROM WF");
ResultSet res=st.executeQuery();
while(res.next()){}
st.close();
System.out.println("dubbyloop.DBCONNECT.connect()");
} catch (SQLException ex) {
try {
Statement stmt = con.createStatement();
stmt.executeQuery("CREATE TABLE WF (FILEPATH CHAR(254) NOT NULL, FILESIZE LONG VARCHAR, WFDATA CLOB(2147483647), PRIMARY KEY (FILEPATH));");
System.out.println("CREATED");
} catch (SQLException ex1) {
Logger.getLogger(DBCONNECT.class.getName()).log(Level.SEVERE, null, ex1);
}
System.out.println(ex);
}
}
}
但我總是得到這個錯誤:
SCHWERWIEGEND: null
java.sql.SQLSyntaxErrorException: Syntaxfehler: Encountered ";" at line 1, column 118.
at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.TransactionResourceImpl.wrapInSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.TransactionResourceImpl.handleException(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedConnection.handleException(Unknown Source)
at org.apache.derby.impl.jdbc.ConnectionChild.handleException(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedStatement.execute(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedStatement.executeQuery(Unknown Source)
at myproject.DBCONNECT.connect(DBCONNECT.java:48)
我不知道我做錯了什么。 我改變了創建查詢中的所有內容。我刪除了semikolon.i刪除了Clob甚至整個Clob的大小。無論我做什么我總是得到同樣的錯誤,不知道出了什么問題。
stmt.executeUpdate("CREATE TABLE WF ("
+ "FILEPATH VARCHAR(254) NOT NULL, "
+ "FILESIZE LONG, "
+ "WFDATA CLOB(2147483647), "
+ "PRIMARY KEY (FILEPATH))");
有一個VARCHAR太多,不需要分號。 CHAR填充空白,因此更好的VARCHAR。
@MickMnemonic正確地提到應該調用executeUpdate而不是executeQuery。
(例如PRIMARY KEY之前的逗號)? 否則 - 一般調試策略:1)找到錯誤的sql語句行(逐個注釋)2)debug-print結果語句3)對目標數據庫進行檢查
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