关于SQL语句的自动生成！（五）

作者：PeterXu  来源：Blog.优快云  Blog: http://blog.youkuaiyun.com/peterreg/
版权声明：原创作品，允许转载，转载时请务必以超链接形式标明文章原始出版、作者信息和本声明。否则将追究法律责任。本文地址：http://blog.youkuaiyun.com/peterreg/archive/2008/04/02/2243132.aspx

接我的上一篇文章《关于SQL语句的自动生成！（四）》，虽然在DotNet Framework3.5 面世以后，可通过LINQ支持SQL的直接查询，但LINQ只支持SQL系列的，SQL2K,SQL2K5，对于ACCESS,ORACLE,MYSQL等不支持。同时平常的一些工具的创作，对于我们的软件水平也大有好处

下面附上DBACCESS的整套代码，供大家分享

public   interface  IClause
     ... {
        void Add(string name, object val);
        void AddWhere(string name, object val);
        void Clear();
        string TableName ...{ set;}
    }

     public   abstract   class  ClauseFactory
     ... {
        public enum Flag
        ...{
            Insert,
            Update,
            Select,
            Delete,
        }

        Create#region Create

        public static IClause Create(string table, Flag category)
        ...{
            BaseClause ret = null;
            switch (category)
            ...{
                case Flag.Insert:
                    ret = new Insert();
                    break;

                case Flag.Update:
                    ret = new Update();
                    break;

                case Flag.Select:
                    ret = new Select();
                    break;

                case Flag.Delete:
                    ret = new Delete();
                    break;

                default:
                    break;
            }
            if (ret != null)
            ...{
                ret.TableName = table;
            }
            return ret;
        }

        #endregion

        BaseClause#region BaseClause

        private abstract class BaseClause : IClause
        ...{
            private string m_strTable = string.Empty;
            private Where m_oWhere = new Where();

            protected BaseClause()
            ...{
                this.m_strTable = string.Empty;
                this.Clear();
            }

            public virtual void Add(string name, object val)
            ...{
            }

            public void AddWhere(string name, object val)
            ...{
                this.m_oWhere.Add(name, val);
            }

            public void Clear()
            ...{
                this.m_oWhere.Clear();
                this.auxClear();
            }

            public string TableName
            ...{
                set ...{ this.m_strTable = value; }
                protected get ...{ return this.m_strTable; }
            }

            public sealed override string ToString()
            ...{
                return this.ToStr + this.m_oWhere.ToString();
            }

            protected abstract string ToStr ...{ get;}
            protected virtual void auxClear() ...{ }
        }

        #endregion

        Insert, Update..Join#region Insert, Update..Join

        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;
            }
        }

        #endregion

    }