Controlling Access to Data

Since you access data in files, effective data management begins with control over the environment of these files. You must choose how to access the data and how and when to limit that access.

In This Section

• How to: Set Data Access
  Explains how to specify the access type, exclusive or shared, when using a table.

• Locking Data
  Discusses methods to manually or automatically lock access to tables and records to manage access in a shared environment.

• Updating Data Using Multiple Form Instances
  Discusses how data is updated and how locks on records may affect other instances of a form.

• How to: Use Data Sessions
  Describes how to use data sessions to ensure that each user in a shared environment has a secure, exact duplicate of the working environment, and to ensure that multiple instances of a form can operate independently.

• Customizing the Environment of a Data Session
  Discusses how you can use private data sessions to establish custom SET command settings within a single session of Visual FoxPro.

• Buffering Data
  Describes data buffering, and how to use it to protect data during updates.

• How to: Enable Buffering
  Explains how to enable record and table buffering to protect data during updates.

• How to: Append and Delete Records in Table Buffers
  Explains how to append and delete records with table buffering enabled.

Reference

• CURSORSETPROP( ) Function
  Specify property settings for a Visual FoxPro table or cursor.

• TABLEUPDATE( ) Function
  Commit changes made to a buffered row, a buffered table, cursor, or cursor adapter.

• TABLEREVERT( ) Function
  Discard changes made to a buffered row or a buffered table or cursor and restore the OLDVAL( ) data for remote cursors and the current disk values for local tables and cursors.

• LOCK( ) Function
  Attempt to lock one or more records in a table.

• Data Session Window
  Use the Data Session window to open and display tables or views, establish temporary relationships, and set work area properties.

Related Sections

• Programming for Shared Access
  Explains how programming for shared access makes it possible for you to create an application that will run on several machines in a network environment.

• Updating Data
  Explains how to update data using buffers, transactions, or views.

• Managing Conflicts When Updating Data
  Discusses how you can anticipate and manage the inevitable conflicts that result from data update operations.

• Buffering Data
  Explains how to buffer data to protect data during updates.