TAAOUpdateSQL provides a mechanism for circumventing what some developers consider an SQL-92 limitation. This usually happens for queries made against multiple tables. If a dataset is read-only by circumstance, it indicates that the DAO returned a read-only result set. If a dataset is read-only by design, the application itself does not provide a user interface for updating data, but may institute a programmatic scheme behind the scenes. A dataset is read-only either by design or circumstance.
Use a TDAOUpdateSQL object to provide SQL statements used to update read-only datasets represented by TDAODataSet components. Provides an object for updating read-only datasets. DAOQuery components can be used with MS Access and others databases like dBase, FoxPro, ODBC.ĭAOQuery components are useful because they can access more than one table at a time (called a ”join” in SQL), automatically access a subset of rows and columns in its underlying table(s), rather than always returning all rows and columns TDAOUpdateSQL Use TDAOQuery to access a database using SQL statements. TDAOQuery encapsulates a dataset with a result set that is based on an SQL statement. TDAOTable is a dataset component used to retrieve data from database tables. It also enables access to dBase, FoxPro, ODBC and other DAO data sources.Ī TDAODataSet component can also work with a subset of records within a database table using filters and SQL statements. TDAODataSet provides native access to MS Access tables and queries. TDAODataSet is a TDataSet descendent that encapsulates an DAO table or query. Use TDAODatabase when a database application requires any of the following control over a database connection:Īpplication-specific database workgroup file (SystemDB) TDAODatabase provides control over a connection to database in a database application.
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