blob object. Instead, if you know that the value of a cursor property contains BLOb data, you use the methods to access that data. Conversely, to store BLOb data in a database, use the blob function.
| Method |
Description
|
| |
|---|
watch and unwatch methods from Object.
cursorName.colName.blobImage (format [, altText] [, align]
[, widthPixels] [, heightPixels] [, borderPixels] [, ismap])
blobImage to create an HTML image tag for a graphic image in a standard format such as GIF or JPEG.
The blobImage method fetches a BLOb from the database, creates a temporary file (in memory) of the specified format, and generates an HTML image tag that refers to the temporary file. The JavaScript runtime engine removes the temporary file after the page is generated and sent to the client.
While creating the page, the runtime engine keeps the binary data that blobImage fetches from the database in active memory, so requests that fetch a large amount of data can exceed dynamic memory on the server. Generally it is good practice to limit the number of rows retrieved at one time using blobImage to stay within the server's dynamic memory limits.
cursor = connobj.cursor("SELECT NAME, THUMB FROM FISHTBL WHERE ID=2")
write(cursor.name + " ")
write(cursor.thumb.blobImage("gif"))
write("<BR>")
cursor.close()
These statements produce this HTML:
Anthia <IMG SRC="LIVEWIRE_TEMP11"><BR>Example 2. The following example creates a cursor from the
rockStarBios table and uses blobImage to display an image retrieved from the photos column:
cursor = database.cursor("SELECT * FROM rockStarBios
WHERE starID = 23")
while(cursor.next()) {
write(cursor.photos.blobImage("gif", "Picture", "left",
30, 30, 0,false))
}
cursor.close()
This example displays an image as if it were created by the following HTML:
<IMG SRC="livewire_temp.gif" ALT="Picture" ALIGN=LEFTThe
WIDTH=30 HEIGHT=30 BORDER=0>
livewire_temp.gif file in this example is the file in which the rockStarBios table stores the BLOb data.
cursorName.colName.blobLink (mimeType, linkText)
mimeType | |
linkText | The text to display in the link. This can be any JavaScript string expression. |
blobLink if you do not want to display graphics (to reduce bandwidth requirements) or if you want to provide a link to an audio clip or other multimedia content not viewable inline.
The blobLink method fetches BLOb data from the database, creates a temporary file in memory, and generates a hypertext link to the temporary file. The JavaScript runtime engine on the server removes the temporary files that blobLink creates after the user clicks the link or sixty seconds after the request has been processed.
The runtime engine keeps the binary data that blobLink fetches from the database in active memory, so requests that fetch a large amount of data can exceed dynamic memory on the server. Generally it is good practice to limit the number of rows retrieved at one time using blobLink to stay within the server's dynamic memory limits.
cursor = connobj.cursor("SELECT NAME, PICTURE FROM FISHTBL WHERE ID=2")
write(cursor.name + " ")
write(cursor.picture.blobLink("image/gif", "Link" + cursor.id))
write("<BR>")
cursor.close()
These statements produce this HTML:
Anthia <A HREF="LIVEWIRE_TEMP2">Link2</A><BR>Example 2. The following example creates a cursor from the
rockStarBios table and uses blobLink to create links to images retrieved from the photos column:
write("Click a link to display an image:<P>")
cursor = database.cursor("select * from rockStarBios")
while(cursor.next()) {
write(cursor.photos.blobLink("image/gif", "Image " + cursor.id))
write("<BR>")
}
cursor.close()
This example generates the following HTML:
Click a link to display an image:<P>The
<A HREF="LIVEWIRE_TEMP1">Image 1</A><BR>
<A HREF="LIVEWIRE_TEMP2">Image 2</A><BR>
<A HREF="LIVEWIRE_TEMP3">Image 3</A><BR>
<A HREF="LIVEWIRE_TEMP4">Image 4</A><BR>
LIVEWIRE_TEMP files in this example are temporary files created in memory by the blobLink method.
Last Updated: 11/13/98 10:22:48