How to create a new SQL Server database from ASP.NET without using script

dotnet ef does not have db clone commands.

Rather than creating script, you can clone/copy database using SSMS. Then update connection string in asp.net application, test and deply. Here is the documentation of MS SQL server. https://learn.microsoft.com/en-us/sql/relational-databases/databases/use-the-copy-database-wizard?view=sql-server-ver15

Any database have the copy/clone feature.

And if you use EF Code First, Please check ef migrations for existing database. https://learn.microsoft.com/en-us/ef/ef6/modeling/code-first/migrations/existing-database

If you need to copy db only using application, you can create stored procedure and execute from application. here is the details.

1. The source database is backed up to a file using dynamic T-SQL execution
2. The backup is then restored to a new database, using the RESTORE DATABASE WITH MOVE OPTION again using dynamic T-SQL

The procedure takes 6 parameters (all parameters should be supplied):

1. Source database name
2. Source database logical data file name
3. Source database logical log file name
4. Backup file name and path
5. Destination database name
6. Destination database folder location for database files

Here is the T-SQL procedure source code:

USE master;
GO 
CREATE PROCEDURE dbo.CloneDBUsingBackupRestore ( 
@SourceDatabaseName VARCHAR(200) 
,@SourceDatafileLogicalName VARCHAR(200) 
,@SourceLogfileLogicalName VARCHAR(200) 
,@BackupFile VARCHAR(2000) 
,@TargetDatabaseName VARCHAR(200) 
,@TargetDatabaseFolder VARCHAR(2000) ) 
AS 
BEGIN 
SET NOCOUNT ON
DECLARE @tsql VARCHAR(2000) 
DECLARE @TargetDataFile VARCHAR(2000) 
DECLARE @TargetLogFile VARCHAR(2000) 
SET @TargetDataFile = @TargetDatabaseFolder + @TargetDatabaseName + '.mdf'; 
SET @TargetLogFile = @TargetDatabaseFolder + @TargetDatabaseName + '.ldf'; 
-- Backup the Source Database
 IF @SourceDatabaseName IS NOT NULL 
BEGIN 
  SET @tsql = CONCAT ( 'BACKUP DATABASE ' ,@SourceDatabaseName 
,' TO DISK = ' ,QUOTENAME(@BackupFile, '''') ) 
PRINT 'Executing query : ' + @tsql; 
EXEC (@tsql) 
END

-- Restore database from the Backup File into target Data File and target Log File 
SET @tsql = CONCAT ( 'RESTORE DATABASE ' ,@TargetDatabaseName 
,' FROM DISK = ' 
,QUOTENAME(@BackupFile, '''') 
,' WITH MOVE ' 
,QUOTENAME(@SourceDatafileLogicalName, '''') ,
' TO ' ,QUOTENAME(@TargetDataFile, '''') ,' 
, MOVE ' ,QUOTENAME(@SourceLogfileLogicalName, '''') 
,' TO ' ,QUOTENAME(@TargetLogFile, '''') ) 
PRINT 'Executing query : ' + @tsql EXEC (@tsql) 
SET NOCOUNT OFF 
END GO

Call Using ASP.Net Code.

using (SqlConnection con = new SqlConnection(connString))
{
   using (SqlCommand cmd = new SqlCommand("dbo.CloneDBUsingBackupRestore", con))
   {
       cmd.CommandType = CommandType.StoredProcedure;
       cmd.Parameters.Add("@SourceDatabaseName", SqlDbType.VarChar).Value 
          ="Northwind";
       cmd.Parameters.Add("@SourceDatafileLogicalName ", SqlDbType.VarChar).Value 
          ="Northwind_Log";
       cmd.Parameters.Add("@BackupFile", SqlDbType.VarChar).Value 
          ="C:\SQL\nw.bak";
       cmd.Parameters.Add("@TargetDatabaseName", SqlDbType.VarChar).Value 
          ="NorthwindClone";
       cmd.Parameters.Add("@TargetDatabaseFolder ", SqlDbType.VarChar).Value 
          ="C:\SQL";
      con.Open();

      cmd.ExecuteNonQuery();  
      con.Close();  
    }
}