///

এনভায়রনমেন্ট ভেরিয়েবল (সংক্ষেপে "**env var**" নামেও পরিচিত) হলো এমন একটি ভেরিয়েবল যা পাইথন কোডের **বাইরে**, **অপারেটিং সিস্টেমে** থাকে এবং আপনার পাইথন কোড (বা অন্যান্য প্রোগ্রাম) দ্বারা যাকে রিড করা যায়।

এনভায়রনমেন্ট ভেরিয়েবলস অ্যাপ্লিকেশনের **সেটিংস** পরিচালনা করতে, পাইথনের **ইনস্টলেশন** প্রক্রিয়ার অংশ হিসেবে, ইত্যাদি কাজে উপযোগী হতে পারে।

## Env Vars তৈরী এবং ব্যবহার

func Expr(expr string, args ...interface{}) clause.Expr {
	return clause.Expr{SQL: expr, Vars: args}
}

// SetupJoinTable setup join table schema
func (db *DB) SetupJoinTable(model interface{}, field string, joinTable interface{}) error {
	var (
		tx                      = db.getInstance()
		stmt                    = tx.Statement
		modelSchema, joinSchema *schema.Schema
	)

      val sortedRules: SortedSet<ByteString> = TreeSet()
      val sortedExceptionRules: SortedSet<ByteString> = TreeSet()
      var totalRuleBytes = 0
      var totalExceptionRuleBytes = 0

      fileSystem.source(publicSuffixListDotDat).buffer().use { source ->
        while (!source.exhausted()) {
          var rule: ByteString = source.readUtf8LineStrict().toRule() ?: continue

          if (rule.startsWith(EXCEPTION_RULE_MARKER)) {

second_user_data = {
    "id": 4,
    "name": "Mary",
    "joined": "2018-11-30",
}

my_second_user: User = User(**second_user_data)
```

/// info

`**second_user_data` şu anlama geliyor:

Key-Value çiftini direkt olarak  `second_user_data` dictionarysine kaydet , yaptığın şey buna eşit olacak: `User(id=4, name="Mary", joined="2018-11-30")`

///

### Editor desteği

						dbName = f.DBName
					}
				}

				if tx.Statement.Distinct {
					expr = clause.Expr{SQL: "COUNT(DISTINCT(?))", Vars: []interface{}{clause.Column{Name: dbName}}}
				} else if dbName != "*" {
					expr = clause.Expr{SQL: "COUNT(?)", Vars: []interface{}{clause.Column{Name: dbName}}}
				}
			}
		}

		tx.Statement.AddClause(clause.Select{Expression: expr})
	}

  class Builder {
    private var notBefore = -1L
    private var notAfter = -1L
    private var commonName: String? = null
    private var organizationalUnit: String? = null
    private val altNames = mutableListOf<String>()
    private var serialNumber: BigInteger? = null
    private var keyPair: KeyPair? = null
    private var signedBy: HeldCertificate? = null
    private var maxIntermediateCas = -1

		)
		if err != nil {
			db.AddError(err)
			return
		}

		db.RowsAffected, _ = result.RowsAffected()

		if db.Statement.Result != nil {
			db.Statement.Result.Result = result
			db.Statement.Result.RowsAffected = db.RowsAffected
		}

		if db.RowsAffected == 0 {
			return
		}

		var (
			pkField     *schema.Field

			clause.NamedExpr{SQL: result.SQL, Vars: result.Vars}.Build(stmt)
			if stmt.SQL.String() != result.Result {
				t.Errorf("generated SQL is not equal, expects %v, but got %v", result.Result, stmt.SQL.String())
			}

			if !reflect.DeepEqual(result.ExpectedVars, stmt.Vars) {
				t.Errorf("generated vars is not equal, expects %v, but got %v", result.ExpectedVars, stmt.Vars)
			}
		})
	}
}

				} else {
					vars[idx] = nullStr
				}
			}
		case []byte:
			if s := string(v); isPrintable(s) {
				vars[idx] = escaper + strings.ReplaceAll(s, escaper, escaper+escaper) + escaper
			} else {
				vars[idx] = escaper + "<binary>" + escaper
			}
		case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
			vars[idx] = utils.ToString(v)
		case float32:

	}

	references := make([]interface{}, 0, len(constraint.References))
	for _, field := range constraint.References {
		references = append(references, clause.Column{Name: field.DBName})
	}
	vars = append(vars, clause.Table{Name: constraint.Name}, foreignKeys, clause.Table{Name: constraint.ReferenceSchema.Table}, references)
	return
}

func (rel *Relationship) ParseConstraint() *Constraint {