# OTL 4.0, Example 245 (user defined string class and LONGs, Oracle 8/8i/9i)

# Example 245 (user defined string class and LONGs, Oracle 8/8i/9i)

This example demonstrates how to use a user defined string class (other than std::string) with the database large string table columns. The user defined string class should be compliant with the std::string, at least with some of the std::strng functions should exist in the user defined string class. See "class user_defined_string" in the example for more detail.

## Source Code

    #include <iostream>
    using namespace std;
    #include <string.h>

    class user_defined_string{
    public:

      user_defined_string(void)
      {
        buf[0]=0;
      }

      user_defined_string(const char* s)
      {
        strcpy(buf,s);
      }

      user_defined_string(const user_defined_string& s)
      {
        strcpy(buf,s.buf);
      }

      ~user_defined_string(){}

      user_defined_string& operator=(const char* s)
      {
        strcpy(buf,s);
        return *this;
      }

      void assign(int size,char filler)
      {
        for(int i=0;i<size;++i)
          buf[i]=filler;
        buf[size]=0;
      }

      void assign(char* temp_buf,int len)
      {
        for(int i=0;i<len;++i)
          buf[i]=temp_buf[i];
        buf[len]=0;
      }

      char& operator[](int ndx)
      {
        return buf[ndx];
      }

      int length(void) const
      {
        return strlen(buf);
      }

      user_defined_string& operator=(const user_defined_string& s)
      {
        strcpy(buf,s.buf);
        return *this;
      }

      const char* c_str(void) const
      {
        return buf;
      }

    protected:

       char buf[70000];

    };

    ostream& operator<<(ostream& s,const user_defined_string& str)
    {
      s<<str.c_str();
      return s;
    }

    // #define OTL_ORA8 // Compile OTL 4.0/OCI8
    // #define OTL_ORA8I // Compile OTL 4.0/OCI8i
    #define OTL_ORA9I // Compile OTL 4.0/OCI9i
    #define OTL_USER_DEFINED_STRING_CLASS_ON
    #define USER_DEFINED_STRING_CLASS user_defined_string
    #include <otlv4.h> // include the OTL 4.0 header file
    r>otl_connect db; // connect object

    void insert()
    // insert rows into table
    {

     user_defined_string f2;
     db.set_max_long_size(70000); // set maximum long string size for connect object

     otl_stream o(1, // buffer size has to be set to 1 for operations with LOBs
                  "insert into test_tab values(:f1<int>,:f2<varchar_long>)",
                     // SQL statement
                  db // connect object
                 );

     for(int i=1;i<=20;++i){
      f2.assign(50001,' ');
      for(int j=0;j<50000;++j)
       f2[j]='*';
      f2[50000]='?';
      f2[50001]=0;
      o<<i<<f2;
     }

    }

    void select()
    {
     user_defined_string f2;
     db.set_max_long_size(70000); // set maximum long string size for connect object

     otl_stream i(1, // buffer size needs to be set to 1 for operations with LOBs
                  "select * from test_tab where f1>=:f11<int> and f1<=:f12<int>*2",
                     // SELECT statement
                  db // connect object
                 );
       // create select stream

     float f1;

     i<<8<<8; // assigning :f11 = 8, :f12 = 8
       // SELECT automatically executes when all input variables are
       // assigned. First portion of output rows is fetched to the buffer

     while(!i.eof()){ // while not end-of-data
      i>>f1>>f2;
      cout<<"f1="<<f1<<", f2="<<f2[0]<<f2[f2.length()-1]<<", len="
          <<f2.length()<<endl;
     }

     i<<4<<4; // assigning :f11 = 4, :f12 = 4
       // SELECT automatically executes when all input variables are
       // assigned. First portion of output rows is fetched to the buffer

     while(!i.eof()){ // while not end-of-data
      i>>f1>>f2;
      cout<<"f1="<<f1<<", f2="<<f2[0]<<f2[f2.length()-1]<<", len="
          <<f2.length()<<endl;
     }

    }

    int main()
    {
     otl_connect::otl_initialize(); // initialize OCI environment
     try{

      db.rlogon("scott/tiger"); // connect to Oracle

      otl_cursor::direct_exec
       (
        db,
        "drop table test_tab",

        otl_exception::disabled // disable OTL exceptions
       ); // drop table

      otl_cursor::direct_exec
       (
        db,
        "create table test_tab(f1 number, f2 long)"
        );  // create table

      insert(); // insert records into table
      select(); // select records from table

     }

     catch(otl_exception& p){ // intercept OTL exceptions
      cerr<<p.msg<<endl; // print out error message
      cerr<<p.stm_text<<endl; // print out SQL that caused the error
      cerr<<p.var_info<<endl; // print out the variable that caused the error
     }

     db.logoff(); // disconnect from Oracle

     return 0;

    }

## Output

    f1=8, f2=*?, len=50001
    f1=9, f2=*?, len=50001
    f1=10, f2=*?, len=50001
    f1=11, f2=*?, len=50001
    f1=12, f2=*?, len=50001
    f1=13, f2=*?, len=50001
    f1=14, f2=*?, len=50001
    f1=15, f2=*?, len=50001
    f1=16, f2=*?, len=50001
    f1=4, f2=*?, len=50001
    f1=5, f2=*?, len=50001
    f1=6, f2=*?, len=50001
    f1=7, f2=*?, len=50001
    f1=8, f2=*?, len=50001

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Copyright © 1996, 2007, Sergei Kuchin, email: skuchin@ispwest.com, skuchin@gmail.com/a>.

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