Specifies one or more fields in a master table to link with corresponding fields in this table in order to establish a master-detail relationship between the tables.
Specifies the name of the data source for a dataset to use as a master table in establishing a detail-master relationship between this table and another one.
This method uses PHP reflection to iterate through published properties (the ones starting with get) and retrieve the properties stored by a previous serialize() call.
Query represents a dataset with a result set that is based on an SQL statement.
Use Query to access one or more tables in a database using SQL statements. Query components can be used with remote database servers (such as Sybase, SQL Server, Oracle, Informix, DB2, and InterBase), with local tables (Paradox, InterBase, dBASE, Access, and FoxPro), and with ODBC-compliant databases.
Query 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.
Sends a query to the server for optimization prior to execution.
Call Prepare to have a remote database server allocate resources for the query and to perform additional optimizations.
If the query will only be executed once, the application does not need to explicitly call Prepare. Executing an unprepared query generates these calls automatically. However, if the same query is to be executed repeatedly, it is more efficient to prevent these automatic calls by calling Prepare explicitly.
Note: When you change the text of a query at runtime, the query is automatically closed and unprepared.
Contains the parameters for a query’s SQL statement.
Access Params at runtime to view and set parameter names and values dynamically (at design time use the editor for the Params property to set parameter information). Index specifies the array element to access.
Contains the text of the SQL statement to execute for the query.
Use SQL to provide the SQL statement that a query component executes when its Open method is called. At design time the SQL property can be edited by invoking the String List editor in the Object Inspector.
The SQL property may contain only one complete SQL statement at a time. In general, multiple “batch” statements are not allowed unless a particular server supports them.