Precompilation for Deployment in visual basic

Connect PDF 417 in visual basic Precompilation for Deployment

To save you from having to read through the whole RFC2821, I provide here a short summary of the relevant parts needed to implement this channel. First, SMTP uses a request/reply syntax normally sent over a TCP connection to port 25 on the server. The client can send a list of commands, and the server replies to them with a status code and a message. The status code is a three-digit number of which the first digit specifies the class. These are shown in Table 14-1. The message that might be sent after the status code is not standardized and should be ignored or used only for reporting errors back to the user. Table 14-1. SMTP Response Code Classes

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The Screens and Graphics utility allows you to configure the screen and graphics card settings. The Screen tab, shown in Figure 6-2, contains the following settings: Screen: This option allows you to select the display monitor that you would like to configure. If you have only one monitor, then you will see only one entry in this list. Monitor model: This option allows you to provide the technical characteristics of your monitor such as horizontal range, vertical refresh rate, and widescreen-capable. You can also select from a list of branded and generic monitors, plug-and-play, and autodetection.

Figure 8-9. Testing the Silverlight navigation application template View 2 23. Notice that you can press the browser s back button to navigate backward in history from View 2, to View 1, and back to the default.

Video playback is similar to audio playback, with the extra wrinkle that you need to display the video somewhere. This process is very similar to the camera viewfinder we created in the last chapter. You will create the Player, obtain a VideoControl, place it somewhere on the Screen, and then start it playing. The most significant difference from video capture is the longer time it will take to start playback, especially if playing a video delivered over the network. The code that follows shows a simple case of playing a video for about 5 seconds and then stopping.

BLEVEL AVG_LEAF_BLOCKS_PER_KEY AVG_DATA_BLOCKS_PER_KEY ---------- ----------------------- ----------------------2 44 246 The cost of the index line is blevel + avg_leaf_blocks_per_key 1. The incremental cost of the table line is avg_data_blocks_per_key. In the special case of a join that uses equality on the entire index, the optimizer changes its cost calculation to use the precalculated values stored in the user_indexes view (although I cannot explain the appearance of that minus 1 ). And, as we saw in 6, these values are based on knowing the actual number of distinct keys, rather than multiplying together the individual selectivities of the column involved. So, in theory, this should give us a more realistic value for the cost of the join. Unfortunately, the calculation of cardinality in this example did not use the same option (although, as we saw in 10, 10g does have a sanity check based on concatenated index cardinality that sometimes comes into play), so there is a serious discrepancy between the cost and the cardinality. In a more complex case, this discrepancy could encourage the optimizer to put this pair of tables at a very early point in an execution plan it seems to get a small number of rows, and they are expensive rows. Since the actual number of rows is much larger than the optimizer has estimated, the knock-on effects further down the plan could be resource-intensive at run time. In principle, of course, although this particular special case ought to be beneficial, it does have an interesting, and sometimes painful, side effect. You may decide to add an extra column to an index to increase precision and reduce the number of redundant rows that some queries examine in a target table. Alternatively, you may choose to add a column to an index so that a popular query can become an index-only query and not visit the underlying table. (We know, of course, from 5 that this may have an undesirable effect on the cost calculations because of its impact on the clustering_factor.) But if you have other queries that used to use the entire index with equality but don t use the new column, those queries will suddenly change their costing arithmetic from the stored result method to the product of selectivities method. And as we have just seen, there are some indexes where this change could result in a very large change to the cost calculation, which could result in a dramatically different execution plan for the join.