1. A method for creating extensible computer applications with a user interface, by cascading sets of retrieval, computation and update requirement specifications to facilitate repetition, decision and execution control logics, without user input of natural, procedural and programming language and without generating any source codes and executable computers programs; said extensible computer application is composed of unlimited levels of components and sub-components; each component is consists of one or more sets of requirement specifications previously created; newly created components consists of multiple existing components are useable to create higher level components; said method for building applications with no limitation in size and complexity; said method provides database product independent Web based access of databases on the Internet preforming the following steps: a. creating a database dictionary/directory in the form of a two way hierarchical structure with a keyword index for describing existing or new databases tables, columns, and data values; b. creating new databases on the Internet; c. keyword scan by the user in said dictionary to identify available keywords; d. searching said directory by keywords to establish entry points to the directory; e. browsing said directory upward or downward by the user from the said entry points to identify information of interest step by step; f. creating retrieval and computation requirement specifications by the user during the directory browsing process; g. creating update and deletion requirement specifications for existing information and addition of new information during the directory browsing process; h. saving, restoring said requirement specifications by name and submitting said requirement specifications to be executed by the computing engine; i. cascading previously saved requirement specifications as components and sub-components to create a newly named requirement specification which can itself be saved as a component or executed; j. specification of said retrieval/update requirements, repetition and decision control logic from said databases during the directory browsing comprise user: selecting one or more tables from said databases; selecting one or more columns and/or column group from said tables; selecting of one or more data values and/or data value groups and/or data value ranges from said columns; selecting common columns from said selected tables, and criterion for the purpose of integrating multiple tables into a single table; said criterion must be based on the selecting of equal, not equal, greater, smaller, greater or equal, smaller or equal values of the selected common columns; selecting sort columns and/or sort order; selecting group-by columns and/or group-by order from said selected tables; k. specification of said computation requirements, decision and execution control logic from said databases during the directory browsing comprise user: selecting one or more tables from said databases; selecting one or more columns and/or column groups from said tables; selecting one or more data values and/or data value ranges and/or data value groups from said tables; selecting group-by columns and/or group-by order; specifying column aggregation operations; specifying row aggregation operations; creating column algebraic and/or logical expressions known as column formulas in said tables; creating row algebraic and/or logical expressions known as row formulas in said tables; l. operands of said row and column formulas can be expressed symbolically in terms of names or name combinations in said dictionary/directory, operand can also be constants and functions provided by the Web application server; said operand can refer to specific data element, specific row or column in the same or different tables; naming scheme of said operands with specific rules provide a method to address data element, row and column of said tables: said operand can also be the name of a row or column formula defined previously; said row formulas, logical expressions and/or aggregations are automatically applied to all the columns of the row unless restricted by other specification of computation requirements; said column formulas, logical expressions and/or aggregations are automatically applied to all the rows of the column unless restricted by other specification of computation requirements; said sets of retrieval/update and computation requirement specifications can be saved and restored with a given name; said operand can also be the name of a set of requirement specifications saved previously, in which case the requirement specifications will be executed upon submission; said formulas and logical expressions can also be expressed in terms of built-in functions provided by the computing engine with said operands as arguments of said functions to facilitate execution control logics; m. said naming scheme used to name operands in row and column formulas are defined as follows: data elements in any table can be named in the form of X.A.B.C.D; said name addresses the data items of column B in the rows of table A in database X with the value of column C equals D; if said name represents more than one data items, it will be used as an operand of an aggregate or built-in function; if X is omitted in the name, X is defaulted to be the database currently selected: if A is omitted, A is defaulted to be the table currently selected; if B is omitted in the name, expressed as A.C.D of database X, said name references all the rows in table A with the value of column C equal D; if C and D are omitted in the name, expressed as A.B of database X, said name references all the data items in column B of table A; if A, C and D are omitted in the name of an operand, said name references all the data items of column B of the table currently selected; if A, B and C are omitted in the name of an operand, said name references all the rows with data value of the first column of the table currently selected equals D; all names of column and row formulas defined within the same set of requirement specification are unique; all names of requirement specifications saved are unique.