关于SQL语句的自动生成！（四）

各派生类的具体实现

      private class Insert : BaseClause
        ...{
            private string m_strName;
            private string m_strValue;

            public override void Add(string name, object val)
            ...{
                if (val == null)
                ...{
                    this.Add(name, "null", false);
                }
                else
                ...{
                    this.Add(name, val.ToString(), val is string || val is DateTime);
                }
            }

            private void Add(string name, string val, bool isref)
            ...{
                if (isref)
                ...{
                    val = "'" + val + "'";
                }
                if (this.m_strName == string.Empty)
                ...{
                    this.m_strName = "[" + name + "]";
                    this.m_strValue = val;
                }
                else
                ...{
                    this.m_strName += ",[" + name + "]";
                    this.m_strValue += "," + val;
                }
            }

            protected override string ToStr
            ...{
                get ...{ return "INSERT INTO [" + base.TableName + "] ( " + this.m_strName + " ) values ( " + this.m_strValue + " )"; }
            }

            protected override void auxClear()
            ...{
                this.m_strValue = string.Empty;
                this.m_strName = string.Empty;
            }
        }

        private class Delete : BaseClause
        ...{
            public Delete()
            ...{
            }

            protected override string ToStr
            ...{
                get ...{ return "DELETE FROM [" + base.TableName + "]"; }
            }
        }

        private class Update : BaseClause
        ...{
            private string m_strUpdate;

            public override void Add(string name, object val)
            ...{
                if (val == null)
                ...{
                    this.Add(name, "null", false);
                }
                else
                ...{
                    this.Add(name, val.ToString(), val is string || val is DateTime);
                }
            }

            private void Add(string name, string val, bool isref)
            ...{
                if (isref)
                ...{
                    val = "'" + val + "'";
                }
                if (this.m_strUpdate == string.Empty)
                ...{
                    this.m_strUpdate = "[" + name + "]=" + val;
                }
                else
                ...{
                    this.m_strUpdate += ",[" + name + "]=" + val;
                }
            }

            protected override string ToStr
            ...{
                get ...{ return "UPDATE [" + base.TableName + "] SET " + this.m_strUpdate; }
            }

            protected override void auxClear()
            ...{
                this.m_strUpdate = string.Empty;
            }
        }

        private class Select : BaseClause
        ...{
            private string m_strSelect;

            public override void Add(string name, object alis)
            ...{
                if (alis == null)
                ...{
                    this.Add(name, name, false);
                }
                else
                ...{
                    this.Add(name, alis.ToString(), false);
                }
            }

            private void Add(string name, string alis, bool isref)
            ...{
                if (this.m_strSelect == string.Empty)
                ...{
                    this.m_strSelect = "[" + name + "] as [" + alis + "]";
                }
                else
                ...{
                    this.m_strSelect += ",[" + name + "] as [" + alis + "]";
                }
            }

            protected override string ToStr
            ...{
                get
                ...{
                    if (this.m_strSelect == string.Empty)
                    ...{
                        this.m_strSelect = "*";
                    }
                    return "SELECT " + this.m_strSelect + " FROM [" + base.TableName + "]";
                }
            }

            protected override void auxClear()
            ...{
                this.m_strSelect = string.Empty;
            }
        }

        private class Where
        ...{
            private string m_strWhere;

            public Where()
            ...{
                this.Clear();
            }

            public void Add(string name, object val)
            ...{
                if (val == null)
                ...{
                    this.Add(name, "null", false);
                }
                else
                ...{
                    this.Add(name, val.ToString(), val is string || val is DateTime);
                }
            }

            private void Add(string name, string val, bool isref)
            ...{
                if (isref)
                ...{
                    val = "'" + val + "'";
                }
                if (this.m_strWhere == string.Empty)
                ...{
                    this.m_strWhere = "[" + name + "]=" + val;
                }
                else
                ...{
                    this.m_strWhere += " and [" + name + "]=" + val;
                }
            }

            public override string ToString()
            ...{
                string strRet = string.Empty;
                if (this.m_strWhere != string.Empty)
                ...{
                    strRet = " Where " + this.m_strWhere;
                }
                return strRet;
            }

            public void Clear()
            ...{
                this.m_strWhere = string.Empty;
            }
        }