Method for querying high performance, transparent distributed spatial database
A distributed and database technology, applied in the information field, can solve problems such as unrealistic, complex applications, and inconformity with the transparency of distributed databases, and achieve the effect of transparent query
Inactive Publication Date: 2009-12-23
CHANGSHU NANJING NORMAL UNIV DEV RES INST
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[0002] At present, there are two main methods to achieve cross-boundary seamless query of distributed spatial databases: one is to convert the global query connection operation into the connection operation of each segment according to the distribution rules of traditional distributed database connections, but the efficiency of query processing is low; Another method is for the user to determine the relevance between the sites, that is, the user determines which relevant local sites to send the query to, this method does not meet the requirements of the transparency of the distributed database, and it is determined by the user himself Data correlation between venues, the application is complicated, and it is actually not realistic
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Embodiment 1
[0022] The specific execution steps of an experimental system are:
[0023] (1) System call: After the user enters the SQL statement on the query interface, the global SQL statement is passed to the distributed spatial data access engine.
[0024](2) Global query decomposition: Distributed query decomposition is divided into two steps. The first step is to realize the parsing of SQL query statements to obtain the syntax tree; the second step is to transform the syntax tree to obtain the merge connection tree.
[0025] (3) Data localization and query optimization: Localize and optimize the merged join tree according to site fragmentation and other information, and call the global data dictionary service to obtain the necessary global information in the process of data localization and query optimization, such as fragments Site, statistical information, selectivity factors of connection operations, etc., use the removal rules and connection conversion rules to realize the optimi...
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The invention discloses an efficient and transparent query method for a distributed spatial database. Based on the spatial topological relation and spatial analysis operation defined by the Open GIS standard, the spatial topological relation operation and the spatial analysis operation are divided into two categories: Disjoint operation and Non-Disjoint operation; Buffer operation and non-Buffer operation, and according to the spatial topological relationship operation and spatial analysis operation, the connection methods of space segments are divided into four types, and three rules are proposed for the cross-boundary connection operation of four types of space segments, and in these three On the basis of the regularity, 7 rules of cross-boundary spatial segment connection optimization method are further proposed, including 3 removal rules and 4 connection transformation rules. Through the optimization of spatial segment connection, efficient and transparent query of distributed spatial database is realized. .
Description
technical field [0001] The invention relates to an efficient and transparent query method for a distributed spatial database, which belongs to the field of information. Background technique [0002] At present, there are two main methods to achieve cross-boundary seamless query of distributed spatial databases: one is to convert the global query connection operation into the connection operation of each segment according to the distribution rules of traditional distributed database connections, but the efficiency of query processing is low; Another method is for the user to determine the relevance between the sites, that is, the user determines which relevant local sites to send the query to, this method does not meet the requirements of the transparency of the distributed database, and it is determined by the user himself The data correlation between venues is complicated to apply, and it is actually not realistic. Contents of the invention [0003] The object of the pre...
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IPC IPC(8): G06F17/30
Inventor 朱欣焰李德仁夏宇呙维周春辉苏科华
Owner CHANGSHU NANJING NORMAL UNIV DEV RES INST