The Esql Sample

This sample consists of a command line SQL parser. SQL statements are filtered through a monitor and sent to the RDBMS.

Compiling

To compile the example:

• Launch EiffelStudio.
• Select Use existing Ace (control file) and click OK.
• Browse to Eiffel52\examples\store\esql\.
• Choose the file that fits your platform and the DBMS you want to use:
  • Ace.odbc.windows.ace on Windows platforms for ODBC DBMS drivers
  • Ace.oracle.windows.ace on Window platforms for Oracle DBMS
  • Ace.oracle.unix.ace on Unix platforms for Oracle DBMS
• Choose the directory where the project will be compiled, by default the same directory containing the Ace file.
• Click OK.

Running

This sample lets you interact with your database through a console.

First you have to enter the database connection information:

• For ODBC:

Database user authentication:
Data Source Name: handson
Name: smith
Password: mypass

Note: Name and Password are no required with ODBC. If you don't need Name and Password, you can simply hit Return when prompted.

• For Oracle:

Database user authentication:
Name: smith@HANDSON
Password: mypass

Note: you have to specify the Oracle User Name and Net Service Name with the syntax <user>@<service> where <user> stands for the User Name and <service> stands for the Net Service Name.

Then you can enter standard SQL queries to interact with your database, for instance:

SQL> select firstname, lastname from CONTACTS where lastname = 'Smith'
John    Smith
SQL>

Note: enter exit to quit the application.

Under the Hood

This sample showcases the use of the 3 basic classes to interact with your database:

• DB_CONTROL to connect and disconnect to your database.
• DB_SELECTION to perform 'select' queries.
• DB_CHANGE to perform SQL queries that output no result.

The whole sample code is contained in the root class:

• ESQL for Oracle.
• ESQL_ODBC for ODBC.