SQL command classes

TSQLCommand is an abstract class, each instance of which is associated with an instance of a counted-pointer memory-management surrogate class:

• TSQLSimpleCommandHandle
• TSQLCommandHandle
• TSQLNativeCommandHandle

Providers need to implement concrete subclasses derived from TSQLCommand. Instances of TSQLCommand must support the member functions revealed by all three surrogate classes. Each SQL command object manages the execution of a single SQL statement. Providers should support multiple, active, SQL command objects for each connection.

TSQLSimpleCommandHandle is a concrete class that is a counted-pointer surrogate for TSQLCommand. It is the base class for TSQLCommandHandle and TSQLNativeCommandHandle. Use this class to declare variables and fields that can hold either a TSQLCommandHandle or a TSQLNativeCommandHandle.

TSQLCommandHandle is a concrete class that is a counted-pointer surrogate for TSQLCommand. It extends the semantics of TSQLSimpleCommandHandle in that it supports parameterized SQL. Because of this additional capability, you might want to use TSQLCommandHandle rather than TSQLSimpleCommandHandle.

TSQLNativeCommandHandle is a concrete class that is a counted-pointer surrogate for TSQLCommand. It extends the semantics of TSQLSimpleCommandHandle by supporting the execution of native SQL statements. While TSQLCommandHandle is easier to use, TSQLNativeCommandHandle provides the flexibility and performance needed by users of the extended client interface.

TSQLParameter mediates the translation of SQL constants into the native form supported by a particular database protocol or datastore. Clients should use TSQLParameterHandle. Providers must handle the translation of CommonPoint data types to text constants appropriate for use in SQL statements by implementing concrete subclasses derived from TSQLParameter.

TSQLParameterHandle allows clients to mediate the translation of SQL constants into the native form supported by a particular database protocol or datastore.

TSQLHint defines the translation from SQLDAS Base Client SQL to datastore-native SQL. Client applications can also choose to use instances of TSQLHint to construct their own native SQL statements for a datastore.

TSQLStandardHint is a concrete class providing SQL construction hints for a standard connection.

TSQLStatement is an abstract utility class that analyzes the structure of a Base Client SQL statement; it is intended for use by both clients and providers.

TSQLStandardStatement creates SQL statement objects that are independent objects that allow clients to analyze the structure of a Base Client SQL statement.

TSQLTransactionHandle is a concrete class that controls the committing or rolling back of a database transaction. For more information about transactions, see "Understanding transactions" on page 21.