Document:     GDSA_TABLE

Purpose:      Describes GDS Table System.

Category:     TABLES
 
File:         gdsa_table.c

Author:       K.G. Begeman

Description:  A table consists of a number of columns which are
              identified by names. Each column can have a number
              of items (called rows) which are all of the same
              data type and in the same (physical) units. The
              items (rows) in a column are stored sequentially in
              a record-like GDS descriptor. The following
              conventions are used:

              1) a table name has a maximum length of eight
              characters
              2) a column name has a maximum length of eight
              characters
              3) a descriptor name "T_tablename_columnname!" holds
              the column header. The column header has three
              variable length records which contain:
                 - data type stored in column (see notes)
                 - comments for the column only
                 - physical units of data in column
              4) a descriptor name "T_tablename_columnname?" holds
              the column data
              5) a descriptor name "T_tablename_????????#" holds
              comments for the whole table

Notes:        1) The column type can be one of the following
              types:
              CHARn   characters, n being the number of characters
                      per item. n cannot be greater then 132.
              INT     integers
              LOG     logicals
              REAL    single precision floating point numbers
              DBLE    double precision floating point numbers

              2) Error codes: Any non-negative number indicates a
              successful completion of the operation.
              Negative values indicate that an error has occured.

              error  routines        meaning
              -66      all       descriptor file not present
              -67   GDSA_CRECOL  illegal data type
                    GDSA_RCxxx   wrong data type in column
                    GDSA_WCxxx   wrong data type in column
              -68   GDSA_RCxxx   reading past end of information
              -69   GDSA_WCxxx   attempt to skip rows in writing
              -70   GDSA_RDCOM   end of information
              -71   GDSA_TABLIS  number of items in list too small
                    GDSA_TABINQ  number of items in list too small

              3) The following routines are now available:

              GDSA_TABINQ   gives information about a GDS table
              GDSA_TABLIS   list all tables present in a GDS
                            descriptor file
              GDSA_DELTAB   deletes a table
              GDSA_COLINQ   gives information about columns in a
                            table
              GDSA_WRCOM    write comments to a GDS table
              GDSA_RDCOM    reads comment from a GDS table
              GDSA_CRECOL   creates a column in a GDS table
              GDSA_DELCOL   deletes a column from a GDS table
              GDSA_WCCHAR   writes character*n items to a column
              GDSA_WCINT     "  "  integer       "    " "   "
              GDSA_WCLOG     "  "  logical       "    " "   "
              GDSA_WCREAL    "  "  real          "    " "   "
              GDSA_WCDBLE    "  "  double        "    " "   "
              GDSA_RCCHAR   reads  character*n items from a column
              GDSA_RCINT     "  "  integer       "     "  "    "
              GDSA_RCLOG     "  "  logical       "     "  "    "
              GDSA_RCREAL    "  "  real          "     "  "    "
              GDSA_RCDBLE    "  "  double        "     "  "    "
              GDSA_ISTABLE  determines whether a GDS descriptor
                            contains table info.

Updates:      Jul 28, 1987: KGB original document created.
              Feb 18, 1989: KGB Some major changes in column types.
              Nov 13, 1990: KGB Converted to C.
              Mar 23, 1994: JPT modified for use with GDS server.