This section briefly describes the menu commands in Cursor Demo. For more information about the ODBC functions that are executed by many of the menu items, see the Microsoft ODBC Programmer’s Reference.
| Command |
Description |
| New |
Opens a new statement handle on the current connection. |
| Connect |
Closes the current data source connection and connects to a new data source. |
| Disconnect |
Disconnects from the current data source. |
| Sql |
Opens the Statement dialog box, which enables you to execute an SQL statement. |
| Table Information |
Opens the Table Information dialog box, which enables you to query various types of information from the database. It contains the following items: |
| Tables | Calls SQLTables with the specified arguments. |
| Columns | Calls SQLColumns to return column information. |
| Procedures | Calls SQLProcedures for procedure information. |
| Statistics | Calls SQLStatistics to retrieve index information. |
| Privileges | Calls SQLTablePrivileges to retrieve privilege information. |
| Qualifier, Owner, Name, and Type | These edit boxes specify arguments for the ODBC functions. For information about ODBC functions, see the Microsoft ODBC Programmer’s Reference. |
| Type Information | Use this box to specify calls to SQLGetTypeInfo to return information about the data types supported by the data source. |
| Options | Opens the Options dialog box, which enables you to set Cursor Demo statement options. The Options dialog box contains the following: |
| Options List Box | Contains the statement attributes for Bind, Concurrency, General, and Scrolling. It enables you to specify values for the selected type. |
| Options Group | Available options for the selected type are displayed in this group. See the descriptions for the following statement options.
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Bind options. This attribute uses SQLSetStmtAttr with an Attribute value of SQL_ATTR_BIND_TYPE. It enables you to set binding by row, single column, all columns, or a specified row or column number.
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Concurrency options. This option uses SQLSetStmtAttr with an Attribute value of SQL_ATTR_CONCURRENCY to specify when fetched data can be updated, and a ValuePtr value as follows:
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Read-Only
Fetched data cannot be updated. (Uses SQL_CONCUR_READ_ONLY.)
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Optimistic by Timestamp
Fetches will not be updated if the timestamp differs from the original. (Uses SQL_CONCUR_ROWVER.)
-
Optimistic by Values
Fetches will not be updated if the values differ from the original. (Uses SQL_CONCUR_VALUES.)
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General options. These options appear when General is selected in the Options list box. They include:
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Asynchronous Processing
This option uses SQLSetStmtAttr with an Attribute value of SQL_ATTR_ASYNC_ENABLE to enable Cursor Demo to perform asynchronous processing.
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Always Fetch First
This option instructs Cursor Demo to always do SQLExtendedFetch with a FetchOrientation value of SQL_FETCH_FIRST after the successful execution of an SQL statement. If this option is not set, no rows will appear in the result set window until you select one of the commands in the Fetch menu.
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Max column width
This option sets the maximum length of data that will be retrieved for any column. The maximum limit of this parameter is set in the MAX_MAXBIND definition of the CRSRDEMO.H file. Because Cursor Demo allocates space for each column in the rowset, it can run out of memory if too many large columns are bound. Make this value smaller if you run out of memory, or increase it if you want to see more data in large columns. It uses SQLSetStmtAttr with an Attribute of SQL_ATTR_MAX_LENGTH.
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Scrolling options. These options use SQLSetStmtAttr with an Attribute value of SQL_ATTR_CURSOR_TYPE to specify permissible movement of the cursor, and a ValuePtr value as follows:
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Forward only
The cursor will scroll in the forward direction only. (Uses SQL_CURSOR_FORWARD_ONLY.)
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Static (scrollable snapshot)
The cursor will scroll in any direction, but the data will not be updated. (Uses SQL_CURSOR_STATIC.)
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Keyset driven
The cursor is fully keyset-driven. (Uses SQL_CURSOR_KEYSET_DRIVEN.)
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Dynamic
The driver only saves and uses the keys for the rows in the rowset. (Uses SQL_CURSOR_DYNAMIC.)
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Rowset size
Defines the number of rows in your rowset.
|
| Close |
Closes the current statement. |
| Close All |
Closes all open statements. |
| Exit |
Exits Cursor Demo. |
| Command |
Description |
| First |
Uses SQLExtendedFetch with a FetchOrientation value of SQL_FETCH_FIRST. (Fetches the first rowset in the result set.) |
| Prev |
Uses SQLExtendedFetch with a FetchOrientation value of SQL_FETCH_PRIOR. (Fetches the previous rowset in the result set.) |
| Next |
Uses SQLExtendedFetch with a FetchOrientation value of SQL_FETCH_NEXT. (Fetches the next rowset in the result set.) |
| Last |
Uses SQLExtendedFetch using a FetchOrientation value of SQL_FETCH_LAST. (Fetches the last rowset in the result set.) |
| Absolute |
Uses SQLExtendedFetch with a FetchOrientation value of SQL_FETCH_ABSOLUTE. (Fetches the rowset starting at the given absolute row number.) |
| Relative |
Uses SQLExtendedFetch with a FetchOrientation value of SQL_FETCH_RELATIVE. (Fetches the rowset starting at the given relative row number.) |
| Delete Row |
Deletes the selected row. |
| Update Row |
Opens the Update Row dialog box, which enables you to change data in the selected row. |