Stored procedures and stored functions coded in C language are called C stored procedures and C stored functions, respectively. They are referred to collectively in this chapter as external C stored routines.

Features of external C stored routines

• There is no overhead for communication between the server and a client.
  Because external C stored routines are processed at the server in the same manner as SQL stored procedures and SQL stored functions, there is no communication overhead between server and client.
  
• The procedure or function itself can be coded in C language.
  Because C instructions can be specified directly, processing can be coded more flexibly than with SQL control statements.
  
• Debugging is easy.
  To debug an SQL stored procedure or an SQL stored function, you need to execute it at the server. In contrast, an external C stored routine can be debugged at the client, as long as the C debugger is installed at the client.