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The syscolumns system catalog table
describes each column in the database. One row exists for each column
that is defined in a table or view.
| Column |
Type |
Explanation |
| colname |
VARCHAR(128) |
Column name |
| tabid |
INTEGER |
Identifying code of table containing
the column |
| colno |
SMALLINT |
Column number
The system sequentially assigns this (from left to right within
each table). |
| coltype |
SMALLINT |
Code indicating
the data type of the column: |
0 = CHAR
1 = SMALLINT
2 = INTEGE R
3 = FLOAT
4 = SMALLFLOAT
5 = DECIMAL
6 = SERIAL *
7 = DATE
8 = MONEY
9 = NULL
10 = DATETIME
11 = BYTE
12 = TEXT |
13 = VARCHAR
14 = INTERVAL
15 = NCHAR
16 = NVARCHAR
17 = INT8
18 = SERIAL8 *
19 = SET
20 = MULTISET
21 = LIST
22 = Unnamed ROW
40 = Variable-length
opaque type
4118 = Named ROW |
| collength |
SMALLINT |
Column length (in bytes) |
| colmin |
INTEGER |
Minimum column length (in bytes) |
| colmax |
INTEGER |
Maximum column length (in bytes) |
extended_id
(IDS) |
INTEGER |
Data type code, from the sysxtdtypes table,
of the data type specified in the coltype column |
* In DB–Access, an offset value
of 256 is always added to these coltype codes
because DB–Access sets SERIAL and SERIAL8 columns
to NOT NULL. |
Extended Parallel Server does not support opaque data types, nor the complex data
types SET, MULTISET, LIST,
unnamed and named ROW.
A composite index on tabid and colno allows
only unique values.
The coltype codes listed on the previous
page can be incremented by bitmaps showing the following features
of the column.
- Bit Value
- Significance When Bit Is Set
- 0x0100
- NULL values are not allowed
- 0x0200
- Value is from a host variable
- 0x0400
- Float-to-decimal for
networked database server
- 0x0800
- DISTINCT data type
- 0x1000
- Named ROW type
- 0x2000
- DISTINCT type from LVARCHAR base
type
- 0x4000
- DISTINCT type from BOOLEAN base
type
- 0x8000
- Collection is processed on client system
For example, the coltype value 4118 for named row types is the decimal representation
of the hexadecimal value 0x1016, which is the same as the hexadecimal coltype value
for an unnamed row type (0 x 016), with
the named-row-type bit set. (The file $INFORMIXDIR/incl/esql/sqltypes.h contains additional
information about syscolumns.coltype codes.)
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