Doc tweak

Author: kubo

README.md

@@ -264,6 +264,9 @@ Rust-oracle and ODPI-C bundled in rust-oracle are under the terms of:
 1. [the Universal Permissive License v 1.0 or at your option, any later version](http://oss.oracle.com/licenses/upl); and/or
 2. [the Apache License v 2.0](http://www.apache.org/licenses/LICENSE-2.0).
 
+Some of doc comments were copied from ODPI-C documentation verbatim.
+Oracle and/or its affiliates hold the copyright of the parts.
+
 [Rust]: https://www.rust-lang.org/
 [ODPI-C]: https://oracle.github.io/odpi/
 [ODPI-C installation document]: https://oracle.github.io/odpi/doc/installation.html

src/conn.rs

@@ -102,9 +102,17 @@ pub struct Info {
     pub db_domain: String,
 
     /// The Oracle Database name associated with the connection
+    ///
+    /// This is the same value returned by the SQL expression
+    /// `SELECT NAME FROM V$DATABASE`.
+    /// Note the values may have different cases.
     pub db_name: String,
 
     /// The Oracle Database instance name associated with the connection
+    ///
+    /// This is the same value returned by the SQL expression
+    /// `SELECT SYS_CONTEXT('USERENV', 'INSTANCE_NAME') FROM DUAL`.
+    /// Note the values may have different cases.
     pub instance_name: String,
 
     /// The Oracle Database service name associated with the connection

src/connection.rs

@@ -1749,6 +1749,8 @@ impl Connection {
     /// # use oracle::test_util;
     /// # let conn = test_util::connect()?;
     /// let info = conn.info()?;
+    /// let instance_name = conn.query_row_as::<String>("SELECT SYS_CONTEXT('USERENV', 'INSTANCE_NAME') FROM DUAL", &[])?;
+    /// assert!(info.instance_name.eq_ignore_ascii_case(&instance_name));
     /// let service_name = conn.query_row_as::<String>("SELECT SYS_CONTEXT('USERENV', 'SERVICE_NAME') FROM DUAL", &[])?;
     /// assert_eq!(info.service_name, service_name);
     /// # Ok::<(), Error>(())