Data bags and the MQAI

A data bag is a means of handling properties or parameters of objects using the IBM MQ Administration Interface (MQAI).

Data Bags

• The data bag contains zero or more data items. These data items are ordered within the bag as they are placed into the bag. This is called the insertion order. Each data item contains a selector that identifies the data item and a value of that data item that can be either an integer, a 64-bit integer, an integer filter, a string, a string filter, a byte string, a byte string filter, or a handle of another bag. Data items are described in details in Types of data item available in the MQAI

  There are two types of selector; user selectors and system selectors. These are described in MQAI Selectors. The selectors are usually unique, but it is possible to have multiple values for the same selector. In this case, an index identifies the particular occurrence of selector that is required. Indexes are described in Indexing in the MQAI.

  A hierarchy of these concepts is shown in Figure 1.

  

  The hierarchy has been explained in a previous paragraph.

Types of data bag

user bag

A simple bag used for user data.

administration bag

A bag created for data used to administer IBM MQ objects by sending administration messages to a command server. The administration bag automatically implies certain options as described in Creating and deleting data bags.

command bag

A bag also created for commands for administering IBM MQ objects. However, unlike the administration bag, the command bag does not automatically imply certain options although these options are available. For more information about options, see Creating and deleting data bags.

group bag

A bag used to hold a set of grouped data items. Group bags cannot be used for administering IBM MQ objects.

In addition, the system bag is created by the MQAI when a reply message is returned from the command server and placed into a user's output bag. A system bag cannot be modified by the user.

Use Data Bags

The different ways of using data bags are shown in the following list:

• We can create and delete data bags Creating and deleting data bags.
• We can send data between applications using data bags Putting and receiving data bags using the MQAI.
• We can add data items to data bags Add data items to bags with the MQAI.
• We can add an inquiry command within a data bag Add an inquiry command to a bag.
• We can inquire within data bags Inquiring within data bags.
• We can count data items within a data bag Counting data items.
• We can change information within a data bag Change information within a bag.
• We can clear a data bag Clearing a bag using the mqClearBag call.
• We can truncate a data bag Truncating a bag using the mqTruncateBag call.
• We can convert bags and buffers Converting bags and buffers.