CREATE TABLE SYS.SYSIQCOLUMN ( table_id UNSIGNED INT NOT NULL, column_id UNSIGNED INT NOT NULL, link_table_id UNSIGNED INT NULL, link_column_id UNSIGNED INT NULL, max_length UNSIGNED INT NOT NULL, approx_unique_count ROWID cardinality ROWID NOT NULL, has_data CHAR(1) NOT NULL, has_original CHAR(1) NOT NULL, original_not_null CHAR(1) NOT NULL, original_unique CHAR(1) NOT NULL, info_location HS_VDORECID NOT NULL, info_recid_size UNSIGNED INT NOT NULL, info_location_size UNSIGNED INT NOT NULL, PRIMARY KEY ( table_id, column_id ) )
Each column in every table is described by one row in SYSIQCOLUMN, which corresponds to a same row in SYSCOLUMN based on the primary key.
table_id The table number uniquely identifies the table to which this column belongs. It corresponds to the table_id column of SYSTABLE.
column_id Each table starts numbering columns at 1. The order of column numbers determines the order that columns are displayed in the command select * from table.
link_table_id For internal use.
link_column_id For internal use.
max_length Indicates the maximum length allowed by the column.
approx_unique_count Approximate number of unique values (cardinality) of this column.
cardinality The actual number of unique values (cardinality) of this column.
has_data Indicates that the column contains data (T/F).
has_original Indicates the join index has the original data (T/F).
original_not_null Indicates the join index column with the original data was NOT NULL (T/F).
original_unique Indicates the join index column with the original data was UNIQUE (T/F).
info_location Not used. Always zero.
