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# XXV. Informix functions

The Informix driver for Online (ODS) 7.x, SE 7.x and Universal Server (IUS) 9.x is implemented in "functions/ifx.ec" and "functions/php3_ifx.h". ODS 7.x support is fairly complete, with full support for BYTE and TEXT columns. IUS 9.x support is partly finished: the new data types are there, but SLOB and CLOB support is still under construction.

> Configuration notes:

> Before you run the "configure" script, make sure that the "INFORMIXDIR" variable has been set.

> The configure script will autodetect the libraries and include directories, if you run "configure --with_informix=yes". You can overide this detection by specifying "IFX_LIBDIR", "IFX_LIBS" and "IFX_INCDIR" in the environment. The configure script will also try to detect your Informix server version. It will set the "HAVE_IFX_IUS" conditional compilation variable if your Informix version >= 9.00.

> Some notes on the use of BLOBs (TEXT and BYTE columns):

> BLOBs are normally addressed by integer BLOB identifiers. Select queries return a "blob id" for every BYTE and TEXT column. You can get at the contents with "string_var = ifx_get_blob($blob_id);" if you choose to get the BLOBs in memory (with : "ifx_blobinfile(0);"). If you prefer to receive the content of BLOB columns in a file, use "ifx_blobinfile(1);", and "ifx_get_blob($blob_id);" will get you the filename. Use normal file I/O to get at the blob contents.

> For insert/update queries you must create these "blob id's" yourself with "ifx_create_blob(..);". You then plug the blob id's into an array, and replace the blob columns with a question mark (?) in the query string. For updates/inserts, you are responsible for setting the blob contents with ifx_update_blob(...).

> The behaviour of BLOB columns can be altered by configuration variables that also can be set at runtime :

> configuration variable : ifx.textasvarchar

> configuration variable : ifx.byteasvarchar

> runtime functions :

> ifx_textasvarchar(0) : use blob id's for select queries with TEXT columns

> ifx_byteasvarchar(0) : use blob id's for select queries with BYTE columns

> ifx_textasvarchar(1) : return TEXT columns as if they were VARCHAR columns, without the use of blob id's for select queries.

> ifx_byteasvarchar(1) : return BYTE columns as if they were VARCHAR columns, without the use of blob id's for select queries.

> configuration variable : ifx.blobinfile

> runtime function :

> ifx_blobinfile_mode(0) : return BYTE columns in memory, the blob id lets you get at the contents.

> ifx_blobinfile_mode(1) : return BYTE columns in a file, the blob id lets you get at the file name.

> If you set ifx_text/byteasvarchar to 1, you can use TEXT and BYTE columns in select queries just like normal (but rather long) VARCHAR fields. Since all strings are "counted" in PHP, this remains "binary safe". It is up to you to handle this correctly. The returned data can contain anything, you are responsible for the contents.

> If you set ifx_blobinfile to 1, use the file name returned by ifx_get_blob(..) to get at the blob contents. Note that in this case YOU ARE RESPONSIBLE FOR DELETING THE TEMPORARY FILES CREATED BY INFORMIX when fetching the row. Every new row fetched will create new temporary files for every BYTE column.

> The location of the temporary files can be influenced by the environment variable "blobdir", default is "." (the current directory). Something like : putenv(blobdir=tmpblob"); will ease the cleaning up of temp files accidentally left behind (their names all start with "blb").

> Automatically trimming "char" (SQLCHAR and SQLNCHAR) data:

> This can be set with the configuration variable

> ifx.charasvarchar : if set to 1 trailing spaces will be automatically trimmed.

> NULL values:

> The configuration variable ifx.nullformat (and the runtime function ifx_nullformat()) when set to true will return NULL columns as the string "NULL", when set to false they return the empty string. This allows you to discriminate between NULL columns and empty columns.

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