Query Types.
Consultations are the objects in a database that can retrieve data from a table, modify and even store the result in another table.
There are several types of queries:
- selection queries.
are queries that extract and show data.
show those data from a table that meet the specified criteria. Once we get the result we see the data to modify (this can be done or not as the query).
A select query generates a logical table (called logical because it is not physically on the hard disk but the computer's memory and every time you open is recalculated.)
- Action queries.
consultations are making changes to records. There are several types of action queries, delete, update, append data and creating tables.
- specific SQL queries.
are queries that can not be defined from the Access QBE grid but have to be defined directly in SQL.
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