What does Query mean?
Query asks the right questions of the database and describes the search query in a search engine. The English word “query” is derived from the Latin “Quaerere” and means “query” or “question”. This is the technical translation of the word or word combination entered in the search field. The query is therefore the interface between the search engine and the searcher. Queries (Web Search Query) read databases (Query Language, SQL), files from other IT systems (Information Retrieval Query Languages), database programs. They are integrated in application programs via functions or can be found in the URLs of websites (query string).
How does the “Query” work?
You enter your search term in the input field of a search engine and confirm it, then the search query (query processor) starts. It is a misconception that the entire Internet is searched for pages matching the search query. This would take far too much time and involve an enormous technical effort. How could this lead to a result in a fraction of a second? But how does it work then? The search engine accesses its database and delivers results based on this data. The first result is pre-selected and the search engine classifies the first result as the most relevant for the search query.
Data is recorded using a web robot system. The data is processed and evaluated in the so-called “Information Retrieval System”, the database system. The Query Processor uses this database and collects all documents that match the search query. The algorithm of the query processor determines the order in which these are displayed.
How can you achieve more accurate results in the search results?
Some search engines offer the option of “advanced search”, where you can narrow down your search further using certain parameters. When entering several search terms, the search engine uses the Boolean operators (e.g. and, or, not) to combine the search terms.
How to search using the query language?
To search databases, query languages are used that send queries to the database. To filter the search results, the queries are equipped with additional parameters (e.g.: roller red). These parameters can usually be freely selected by the user, but can also be created invisibly for the user by the system (e.g.: “Hidden” parameters). The more precisely a query language affects the dataset, the more strongly it is named (cardinality).
The most important query languages in information systems are:
- Query by Example: Query by Example (QBE) searches a relational database using examples; the commands are formulated in the form of a table structure
- XQuery for XML-based systems: XQuery, the abbreviation for XML Query Language, is a W3C-compliant query language for reading XML databases. Path expressions with XPath and six other possible functions to which parameters can be communicated are used. The sequences can also be edited by appending them together (comma operator). Values can also be added to the sequences, deleted, rearranged or reordered.
- SQL as a query language for relational databases: SQL (Structured Query Language) includes not only the query function for querying data sets, but also commands for defining and manipulating tables and data in relational database systems. Developed on the basis of relational algebra and has become the standard query language of RDBMS. The language elements of SQL can be divided into DML commands for changing, inserting and deleting data, into DDL commands for defining the database schema and also for DCL commands, which are different for transaction control and rights management. Queries to the tables of the relational database system are formulated in SQL with the SELECT command, to which further parameters can be passed.
What does Query mean?
Query asks the right questions of the database and describes the search query in a search engine. The English word “query” is derived from the Latin “Quaerere” and means “query” or “question”. This is the technical translation of the word or word combination entered in the search field. The query is therefore the interface between the search engine and the searcher. Queries (Web Search Query) read databases (Query Language, SQL), files from other IT systems (Information Retrieval Query Languages), database programs. They are integrated in application programs via functions or can be found in the URLs of websites (query string).
How does the “Query” work?
You enter your search term in the input field of a search engine and confirm it, then the search query (query processor) starts. It is a misconception that the entire Internet is searched for pages matching the search query. This would take far too much time and involve an enormous technical effort. How could this lead to a result in a fraction of a second? But how does it work then? The search engine accesses its database and delivers results based on this data. The first result is pre-selected and the search engine classifies the first result as the most relevant for the search query.
Data is recorded using a web robot system. The data is processed and evaluated in the so-called “Information Retrieval System”, the database system. The Query Processor uses this database and collects all documents that match the search query. The algorithm of the query processor determines the order in which these are displayed.
How can you achieve more accurate results in the search results?
Some search engines offer the option of “advanced search”, where you can narrow down your search further using certain parameters. When entering several search terms, the search engine uses the Boolean operators (e.g. and, or, not) to combine the search terms.
How to search using the query language?
To search databases, query languages are used that send queries to the database. To filter the search results, the queries are equipped with additional parameters (e.g.: roller red). These parameters can usually be freely selected by the user, but can also be created invisibly for the user by the system (e.g.: “Hidden” parameters). The more precisely a query language affects the dataset, the more strongly it is named (cardinality).
The most important query languages in information systems are:
- Query by Example: Query by Example (QBE) searches a relational database using examples; the commands are formulated in the form of a table structure
- XQuery for XML-based systems: XQuery, the abbreviation for XML Query Language, is a W3C-compliant query language for reading XML databases. Path expressions with XPath and six other possible functions to which parameters can be communicated are used. The sequences can also be edited by appending them together (comma operator). Values can also be added to the sequences, deleted, rearranged or reordered.
- SQL as a query language for relational databases: SQL (Structured Query Language) includes not only the query function for querying data sets, but also commands for defining and manipulating tables and data in relational database systems. Developed on the basis of relational algebra and has become the standard query language of RDBMS. The language elements of SQL can be divided into DML commands for changing, inserting and deleting data, into DDL commands for defining the database schema and also for DCL commands, which are different for transaction control and rights management. Queries to the tables of the relational database system are formulated in SQL with the SELECT command, to which further parameters can be passed.
