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This component executes SQL queries on a DB. It has the following properties:
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Property
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Description
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DatabaseName
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connection name (name of the TfrxADODatabase component)
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FieldAliases
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enables aliases to be set for the dataset fields
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Filter
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expression for filtering records
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Filtered
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whether filtered or not
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Master
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master dataset
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Params
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list of query parameters
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SQL
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Query text
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UserName
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alias for the dataset, used in code
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IgnoreDupParams
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when True allows parameters with duplicate names. The name of the Query parameters will not be edited in the parameter editor
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The “Active”, “DatabaseName”, “FieldAliases”, “Filter”, “Filtered” and “Master” properties are similar to those of the “TfrxADOTable” component described above. The “SQL” property has its own editor for entering the SQL query.
The “Params” property also has its own editor. It is enabled when a Query text contains parameters.
A parameter can be one of two types : its value either derived from the master-source or set as a discrete value (either an absolute value, as shown above, or linked to a variable or to an object property).
When a parameter is derived from the data master-set the “TfrxADOQuery.Master” property has to be set. This dataset must contain a field of the same name as the parameter. Neither the parameter type nor its value has to be specified.
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