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The following Information Schema views are described in
this section:
- tables
- columns
- sql_languages
- server_info
In order to accept long identifier names, most of the columns
in the views are defined as VARCHAR data
types with large maximum sizes.
The tables Information Schema View
The tables Information Schema view
contains one row for each table to which you have access. It contains
the following columns.
| Column |
Data Type |
Explanation |
| table_schema |
VARCHAR(32) |
Name of owner of table |
| table_name |
VARCHAR(128) |
Name of table or view |
| table_type |
VARCHAR(128) |
BASE TABLE for table or VIEW for view |
| remarks |
VARCHAR(255) |
Reserved for future use |
The visible rows in the tables view depend
on your privileges. For example, if you have one or more privileges
on a table (such as Insert, Delete, Select, References, Alter, Index,
or Update on one or more columns), or if privileges are granted
to PUBLIC, you see the row that describes
that table.
The columns Information Schema View
The columns Information Schema view
contains one row for each accessible column. It contains the following
columns.
| Column |
Data Type |
Explanation |
| table_schema |
VARCHAR(128) |
Name of owner of table |
| table_name |
VARCHAR(128) |
Name of table or view |
| column_name |
VARCHAR(128) |
Name of the column in the table or view |
| ordinal_position |
INTEGER |
Position of the column within its table
The ordinal_position value is a sequential number
that starts at 1 for the first column. This is an Informix extension
to XPG4. |
| data_type |
VARCHAR(254) |
Name of the data type of the column, such as CHARACTER or DECIMAL |
| char_max_length |
INTEGER |
Maximum length (in bytes) for character data
types; NULL otherwise |
| numeric_precision |
INTEGER |
Uses one of the following values:
- Total number of digits for exact numeric data types (DECIMAL, INTEGER, MONEY, SMALLINT)
- Number of digits of mantissa precision (machine-dependent) for approximate
data types (FLOAT, SMALLFLOAT)
- NULL for all other data types.
|
| numeric_prec_radix |
INTEGER |
Uses one of the following values:
- 2 = Approximate data types (FLOAT and SMALLFLOAT)
- 10 = Exact numeric data types (DECIMAL, INTEGER, MONEY,
and SMALLINT)
- NULL for all other data types
|
| numeric_scale |
INTEGER |
Number of significant digits to the right of the
decimal point for DECIMAL and MONEY data types
0 for INTEGER and SMALLINT types
NULL for all other data types |
| datetime_precision |
INTEGER |
Number of digits in the fractional part of the
seconds for DATE and DATETIME columns; NULL otherwise
This column is an Informix extension to XPG4. |
| is_nullable |
VARCHAR(3) |
Indicates whether a column allows NULL values;
either YES or NO |
| remarks |
VARCHAR(254) |
Reserved for future use |
The sql_languages Information Schema View
The sql_languages Information
Schema view contains a row for each instance of conformance to standards
that the current database server supports. The sql_languages view
contains the following columns.
| Column |
Data Type |
Explanation |
| source |
VARCHAR(254) |
Organization defining this SQL version |
| source_year |
VARCHAR(254) |
Year the source document was approved |
| conformance |
VARCHAR(254) |
Standard to which the server conforms |
| integrity |
VARCHAR(254) |
Indication of whether this is an integrity enhancement
feature; either YES or NO |
| implementation |
VARCHAR(254) |
Identification of the SQL product of the vendor |
| binding_style |
VARCHAR(254) |
Direct, module, or other binding style |
| programming_lang |
VARCHAR(254) |
Host language for which binding style is adapted |
The sql_languages view is completely visible
to all users.
The server_info Information Schema View
The server_info Information Schema
view describes the database server to which the application is currently
connected. It contains two columns.
| Column |
Data Type |
Explanation |
| server_attribute |
VARCHAR(254) |
An attribute of the database server |
| attribute_value |
VARCHAR(254) |
Value of the server_attribute as
it applies to the current database server |
Each row in this view provides information about one attribute. X/Open-compliant
databases must provide applications with certain required information
about the database server.
The server_info view includes the following server_attribute information.
| server_attribute |
Explanation |
| identifier_length |
Maximum number of bytes for a user-defined identifier |
| row_length |
Maximum number of bytes in a row |
| userid_length |
Maximum number of bytes in a user name |
| txn_isolation |
Initial transaction isolation level for the database
server:
Read Uncommitted( = Default isolation level for databases with no transaction logging;
also called Dirty Read)
Read Committed( = Default isolation level for databases that are not ANSI-compliant
but that support explicit transaction logging)
Serializable( = Default isolation level for ANSI-compliant databases;
also called Repeatable Read) |
| collation_seq |
Assumed ordering of the character set for the
database server
The following values are possible:
ISO 8859-1EBCDIC
The default Informix representation shows ISO 8859-1. |
The server_info view is completely visible
to all users.
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