VARCHAR(MAX) for params in mssql

Author: lovasoa

CHANGELOG.md

@@ -131,7 +131,7 @@ and to create JSON APIs.
 #### Other sql syntax enhancements
 
  - SQLPage now supports the custom `CONVERT` expression syntax for MS SQL Server, and the one for MySQL.
- - SQLPage now supports the `VARCHAR(MAX)` type in MS SQL Server.
+ - SQLPage now supports the `VARCHAR(MAX)` type in MS SQL Server and uses it for all variables bound as parameters to your SQL queries (we used to use `VARCHAR(8000)` before).
  - `INSERT INTO ... DEFAULT VALUES ...` is now supported 
 
 ### Other news

src/webserver/database/sql.rs

@@ -274,10 +274,7 @@ impl ParameterExtractor {
         let data_type = match self.db_kind {
             // MySQL requires CAST(? AS CHAR) and does not understand CAST(? AS TEXT)
             AnyKind::MySql => DataType::Char(None),
-            AnyKind::Mssql => DataType::Varchar(Some(CharacterLength::IntegerLength {
-                length: 8000,
-                unit: None,
-            })),
+            AnyKind::Mssql => DataType::Varchar(Some(CharacterLength::Max)),
             _ => DataType::Text,
         };
         let value = Expr::Value(Value::Placeholder(name));
@@ -664,7 +661,7 @@ mod test {
         let parameters = ParameterExtractor::extract_parameters(&mut ast, AnyKind::Mssql);
         assert_eq!(
             ast.to_string(),
-            "SELECT CONCAT('', CAST(@p1 AS VARCHAR(8000))) FROM [a schema].[a table]"
+            "SELECT CONCAT('', CAST(@p1 AS VARCHAR(MAX))) FROM [a schema].[a table]"
         );
         assert_eq!(parameters, [StmtParam::GetOrPost("1".to_string()),]);
     }