从MySQL迁移到MS Azure SQL数据库

Question

I have a J2EE web application that issues parameterized SQL queries to a MySQL back-end. I need to replace the back-end with MS Azure SQL Database. I have migrated the DB and data over to MS Azure SQL Database. However all my queries from the app are failing. For example the following query (shown with the wrapping code) runs perfectly fine in the Management Studio but fails in the java code:

PreparedStatement statement = dbConnection.prepareStatement("SELECT * FROM [mydb].[apps] WHERE [key] = ?;");
statement.setString(1, appKey);
ResultSet resultSet = statement.executeQuery();

The error I get is:

com.microsoft.sqlserver.jdbc.SQLServerException: Incorrect syntax near the keyword 'key'.

I tried various things like removing the [], qualifying the column name with the table name, etc. but nothing works.

Also one more question: The JDBC connection I am using string includes the database name (mydb) so I don't want to include it in each of my SQL statement. I never did for MySQL so I'd rather avoid doing it now since it would require me to manually add the DB name to each statement in the code. However if I remove the DB name from the above query it again fails with error Invalid object name 'apps' . Why isn't the DB specified in the connection string being used as the default one? The connection string I am using is jdbc:sqlserver://{servername}.database.windows.net:1433;database=mydb;user={username}@{servername};password={password};encrypt=true;trustServerCertificate=false;hostNameInCertificate=*.database.windows.net;loginTimeout=30;

BTW I am using the Azure SQL Database V12 and connecting via Microsoft JDBC Driver 4.2 for SQL Server.

Answer 1

I tried to reproduce your issue, but my sample code ran fine. Per my experience, I think that the issue cause is by using incorrect table name form.

The MSSQL table name completed form is <db_name>.<owner_name>.<table_name>. Its short form could be <owner_name>.<table_name> or <table_name>. The item can be <item> or [<item>].

Sample Code (for Azure SQL Database, the same principle as MSSQL on Azure VM):

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class Test {

    public static void main(String[] args) throws SQLException, ClassNotFoundException {
        Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
        String jdbcUrl = "jdbc:sqlserver://<host_name>:1433;database=<db_name>;";
//The completed connection string is jdbc:sqlserver://<host_name>:1433;database=<db_name>;user=<user like username@server_name>;password={your_password_here};encrypt=true;hostNameInCertificate=*.database.windows.net;loginTimeout=30;
        String user = "<user>";
        String password = "<password>";
        Connection conn = DriverManager.getConnection(jdbcUrl, user, password);
        String sql = "SELECT * FROM person WHERE name = ?;" // My test table is 'person'
// The table name could be person, [person], dbo.person, [dbo].[person], <db_name>.dbo.person, [<db_name>].[dbo].[person]
        PreparedStatement statement = conn.prepareStatement(sql);
        statement.setString(1, "Peter Pan");
        ResultSet rs = statement.executeQuery();
        while(rs.next()) {
            System.out.println(rs.getLong("id")+","+rs.getString("name"));
        }
    }
}

I suggest you to use the third-party Universal Database Management Tool "Dbeaver". It based on Eclipse and used JDBC Driver to connect kinds of Database include MSSQL. You can create db connection to MSSQL on Azure VM and test SQL queries.

Best Regards.