Multiple query method of database

Abstract

The invention discloses a multiple query method of a database. The multiple query method includes the following steps that a, whether values of query key fields corresponding to the second serial number to be queried to the last serial number to be queried are identical to the value of a query key field corresponding to an initial serial number to be queried is judged one by one, and the judgment result of different first serial numbers in at least one continuous serial number is obtained so as to obtain a serial number set; b, the sequential numbers in the sequential number set serve as initial serial numbers to be queried, the sequential numbers between the initial sequential numbers and the next sequential numbers in the sequential number set serve as the second serial numbers to be queried to the last serial numbers to be queried, and the step a is repeated; c, the step a and the step b are repeated until obtained sequential number sets are empty sets, the last sequential numbers, corresponding to the empty sets, of the sequential number sets are obtained, and therefore repeating cut points of the values of the query key fields are obtained.

Description

technical field [0001] The invention relates to the technical field of data query, in particular to a method for data in multiple query tables of a database. Background technique [0002] The ultimate goal of designing a database and creating a database is to use the database. Working with data is the work of SQL (Structured Query Language, SQL for short) data manipulation language. The core of DML (Data manipulation language) is the select (select, here refers to a function commonly used in a computer SQL database, used to select objects) command, which is also the only command to query the database. select is the largest and most complex of the SQL commands. Many operations of select are derived from relational algebra and contain many contents of relational algebra. Even in SQLite (SQLite is an open source, embedded relational database, it does not have an independently running process, and coexists with all service applications in the application process. SQLite is po...

AI Technical Summary

Problems solved by technology

[0003] At present, we commonly use the method of querying table data. When the query condition is determined, we can explicitly use SQL statements to realize it. However, when the query condition is a dynamic combination of multiple conditions, the query statement will be broken due to too many branches and the IF statement. The multiple nesting becomes quite complicated, especially under the embedded operating system, the digestion memory is limited

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