Method and system for accessing distinct type data-base

Abstract

The invention provides a method for accessing data bases of different types, which includes: receive a general SQL sentence independent of an objective data base; judge the type of the objective data base; according to the type of the objective data base, translate the general SQL sentence into the SQL sentence which is executed in the special objective data base; deliver the translated SQL sentence to the special objective data base. The method is able to screen the difference in the different data bases, and the application program does not need to care about the type of the running objective data base. The invention also provides a system for accessing the data bases of different types.

Description

technical field [0001] The invention relates to the field of databases, in particular to a method and system for accessing different types of databases. Background technique [0002] In addition to implementing standard SQL syntax, existing database products also support their own unique SQL syntax, which is not universal. For example: the following statement is supported in SQL SERVER: SELECT TOP 100*FROM t, but because the TOP keyword is not supported under DB2, this statement cannot be compiled and executed correctly and must be written as an equivalent statement: SELECT*FROM tFETCH FIRST 100 ROWS ONLY. It can be seen that the realization of the same function, that is, selecting the first 100 records from table t, can be realized in both SQL SERVER and DB2, but the way of realization, that is, the submitted query statement is not the same. Another example: DB2 supports the following statement: update t as t1... But this statement will report a syntax error when it is ex...

AI Technical Summary

Problems solved by technology

[0005] 1. Restrict the flexibility of using SQL: Object-oriented statements are fundamentally different from structured statements, and the current database systems are basically relational databases. This situation determines that object-oriented statements cannot be as flexible as structured statements. Integrates well with database systems

[0006] 2. It is difficult to describe complex SQL statements: developers submit object statements, but the generated SQL statements are structured statements

This difference makes the tool itself unable to handle complex SQL statements. On the other hand, it will be difficult for developers to convert complex associated statements into objectified statements.

[0007] 3. To use a database-specific statement, it must be done through the interface

The two interfaces have caused a lot of trouble for developers during the use process. The appropriate interface must be selected, and the interface must be changed synchronously when modifying the statement

Images