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External connection management method, device, server and storage medium

A management method and external connection technology, applied in the database field, can solve problems such as increased system burden, large amount of data, and cumbersome execution process

Active Publication Date: 2020-11-13
SHANGHAI DAMENG DATABASE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the traditional outer join execution method, when there is a filter condition above the outer join, and the filter condition is that the connection column of the non-reference table is empty, the outer join needs to be performed first, and the result of the outer join is used as the input of the filter condition , to filter line by line to get the result. This execution method is cumbersome, which reduces the execution efficiency of the outer join, and after the outer join is executed, the output result data volume is large, which requires a large amount of memory and increases the burden on the system.

Method used

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  • External connection management method, device, server and storage medium
  • External connection management method, device, server and storage medium
  • External connection management method, device, server and storage medium

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0040] figure 1 This is a flowchart of an external connection management method provided by Embodiment 1 of the present invention. The method can be executed by an external connection management device integrated in a server. Specifically, the method includes the following steps:

[0041] S110. Acquire a first data table and a second data table for executing the external connection.

[0042] Connection is the main feature of the database model. When multiple data table queries are involved in the database, the information stored in multiple data tables can be queried through the connection operation. Specifically, the connection of the data table includes inner joins and outer joins. Inner joins can also be called natural joins or equivalent joins. All rows that do not match rows in other joined tables are deleted from the result table, that is, the inner join is Returns the intersection of two or more data tables.

[0043] Outer joins include left outer joins, right outer joins, an...

Embodiment 2

[0058] figure 2 This is a flowchart of an external connection management method provided in the second embodiment of the present invention, which is embodied on the basis of the above-mentioned embodiment. Specifically, the method includes the following steps:

[0059] S210. Acquire a first data table and a second data table for executing the external connection.

[0060] S220: Parse the outer join query statement input by the user, where the outer join query statement includes an outer join operator and a connection condition.

[0061] S230. Whether the external connection query statement meets the set first execution condition, if yes, execute S240; otherwise, execute S260.

[0062] Specifically, according to the analysis result, it is judged whether the outer join query statement meets the set first execution condition. If it is satisfied, S240 is executed according to the first execution plan; otherwise, S260 is executed according to the second execution plan. One execution condi...

Embodiment 3

[0076] Figure 5 This is a structural diagram of an external connection management device provided in Embodiment 3 of the present invention. The device can execute the external connection management method described in any of the foregoing embodiments. Specifically, the device includes:

[0077] The obtaining module 310 is used to obtain the first data table and the second data table for executing the external connection;

[0078] The parsing module 320 is used to parse the outer join query statement input by the user, the outer join query statement including the outer join operator and the join condition;

[0079] The discarding module 330 is configured to discard the first result data row obtained when the connection condition is satisfied in the first data table and the second data table if the external connection query statement meets the set first execution condition.

[0080] The third embodiment of the present invention provides an external connection management device, which pa...

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Abstract

The invention discloses an external connection management method and device, a server and a storage medium. The method comprises the following steps of: obtaining a first data table and a second datatable which execute external connection, and analyzing an external connection query statement input by a user, the external connection query statement comprising an external connection operator and aconnection condition, and if the external connection query statement satisfies a set first execution condition, discarding a first result data line obtained when the connection condition is satisfiedin the first data table and the second data table. According to the technical scheme, the first result data line obtained when the connection condition is met in the first data table and the second data table is discarded, the execution process of the external connection is simplified, the output result data size of the external connection is reduced, and the execution performance of the externalconnection is improved.

Description

Technical field [0001] The embodiments of the present invention relate to the field of database technology, and in particular to an external connection management method, device, server, and storage medium. Background technique [0002] Outer join is a standard connection operation in database query connection operation, including left outer join, right outer join and full outer join. The left outer join returns all the data rows of the first data table and the data rows that meet the connection conditions in the second data table, and the right outer join returns all the data rows of the second data table and the data rows that meet the connection conditions in the first data table. The return result of the full outer join is the combination of the left outer join and the return result of the right outer join. [0003] We define the table that returns all data rows in the outer join as the reference table, such as the first data table in the left outer join. When there is no data...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F16/2455
Inventor 张钦万伟
Owner SHANGHAI DAMENG DATABASE