Update CLI generate entity schema argument behavior

sea-orm-cli/README.md

@@ -9,5 +9,9 @@ cargo run -- -h
 Running Entity Generator:
 
 ```sh
-cargo run -- generate entity -u mysql://sea:sea@localhost/bakery -s bakery -o out
+# MySQL (`--database-schema` option is ignored) 
+cargo run -- generate entity -u mysql://sea:sea@localhost/bakery -o out
+
+# PostgreSQL
+cargo run -- generate entity -u postgres://sea:sea@localhost/bakery -s public -o out
 ```

sea-orm-cli/src/cli.rs

@@ -21,8 +21,10 @@ pub fn build_cli() -> App<'static, 'static> {
                         .long("database-schema")
                         .short("s")
                         .help("Database schema")
+                        .long_help("Database schema\n \
+                        - For MySQL, this argument is ignored.\n \
+                        - For PostgreSQL, this argument is optional with default value 'public'.")
                         .takes_value(true)
-                        .required(true)
                         .env("DATABASE_SCHEMA"),
                 )
                 .arg(

sea-orm-cli/src/main.rs

@@ -23,13 +23,14 @@ async fn run_generate_command(matches: &ArgMatches<'_>) -> Result<(), Box<dyn Er
     match matches.subcommand() {
         ("entity", Some(args)) => {
             let url = args.value_of("DATABASE_URL").unwrap();
-            let schema = args.value_of("DATABASE_SCHEMA").unwrap();
             let output_dir = args.value_of("OUTPUT_DIR").unwrap();
 
             let table_stmts = if url.starts_with("mysql://") {
                 use sea_schema::mysql::discovery::SchemaDiscovery;
                 use sqlx::MySqlPool;
 
+                let url_parts: Vec<&str> = url.split("/").collect();
+                let schema = url_parts.last().unwrap();
                 let connection = MySqlPool::connect(url).await?;
                 let schema_discovery = SchemaDiscovery::new(connection, schema);
                 let schema = schema_discovery.discover().await;
@@ -42,6 +43,7 @@ async fn run_generate_command(matches: &ArgMatches<'_>) -> Result<(), Box<dyn Er
                 use sea_schema::postgres::discovery::SchemaDiscovery;
                 use sqlx::PgPool;
 
+                let schema = args.value_of("DATABASE_SCHEMA").unwrap_or("public");
                 let connection = PgPool::connect(url).await?;
                 let schema_discovery = SchemaDiscovery::new(connection, schema);
                 let schema = schema_discovery.discover().await;