# db2_columns

(PECL ibm_db2 >= 1.0.0)

db2_columns — Returns a result set listing the columns and associated metadata for a table

### 说明

db2_columns ( resource `$connection` [, string `$qualifier` [, string `$schema` [, string `$table-name` [, string `$column-name` ]]]] ) : resource

Returns a result set listing the columns and associated metadata for a table.

### 参数

`connection`

  A valid connection to an IBM DB2, Cloudscape, or Apache Derby database.

`qualifier`

  A qualifier for DB2 databases running on OS/390 or z/OS servers. For other databases, pass `NULL` or an empty string.

`schema`

  The schema which contains the tables. To match all schemas, pass '%'.

`table-name`

  The name of the table or view. To match all tables in the database, pass `NULL` or an empty string.

`column-name`

  The name of the column. To match all columns in the table, pass `NULL` or an empty string.

### 返回值

Returns a statement resource with a result set containing rows describing the columns matching the specified parameters. The rows are composed of the following columns:

Column name | Description
--- | ---
TABLE_CAT | Name of the catalog. The value is NULL if this table does not have catalogs.
TABLE_SCHEM | Name of the schema.
TABLE_NAME | Name of the table or view.
COLUMN_NAME | Name of the column.
DATA_TYPE | The SQL data type for the column represented as an integer value.
TYPE_NAME | A string representing the data type for the column.
COLUMN_SIZE | An integer value representing the size of the column.
BUFFER_LENGTH | Maximum number of bytes necessary to store data from this column.
DECIMAL_DIGITS | The scale of the column, or `NULL` where scale is not applicable.
NUM_PREC_RADIX | An integer value of either 10 (representing an exact numeric data type), 2 (representing an approximate numeric data type), or `NULL` (representing a data type for which radix is not applicable).
NULLABLE | An integer value representing whether the column is nullable or not.
REMARKS | Description of the column.
COLUMN_DEF | Default value for the column.
SQL_DATA_TYPE | An integer value representing the size of the column.
SQL_DATETIME_SUB | Returns an integer value representing a datetime subtype code, or `NULL` for SQL data types to which this does not apply.
CHAR_OCTET_LENGTH | Maximum length in octets for a character data type column, which matches COLUMN_SIZE for single-byte character set data, or `NULL` for non-character data types.
ORDINAL_POSITION | The 1-indexed position of the column in the table.
IS_NULLABLE | A string value where 'YES' means that the column is nullable and 'NO' means that the column is not nullable.

### 参见

- db2_column_privileges() - Returns a result set listing the columns and associated privileges for a table
- db2_foreign_keys() - Returns a result set listing the foreign keys for a table
- db2_primary_keys() - Returns a result set listing primary keys for a table
- db2_procedure_columns() - Returns a result set listing stored procedure parameters
- db2_procedures() - Returns a result set listing the stored procedures registered in a database
- db2_special_columns() - Returns a result set listing the unique row identifier columns for a table
- db2_statistics() - Returns a result set listing the index and statistics for a table
- db2_table_privileges() - Returns a result set listing the tables and associated privileges in a database
- db2_tables() - Returns a result set listing the tables and associated metadata in a database