使用有限多例模式管理数据库结构信息(二)
column description has the following columns:
TABLE_CAT String => table catalog (may be null)
TABLE_SCHEM String => table schema (may be null)
TABLE_NAME String => table name
COLUMN_NAME String => column name
DATA_TYPE int => SQL type from java.sql.Types
TYPE_NAME String => Data source dependent type name, for a UDT the type name is fully qualified
COLUMN_SIZE int => column size.
BUFFER_LENGTH is not used.
DECIMAL_DIGITS int => the number of fractional digits. Null is returned for data types where DECIMAL_DIGITS is not applicable.
NUM_PREC_RADIX int => Radix (typically either 10 or 2)
NULLABLE int => is NULL allowed.
columnNoNulls - might not allow NULL values
columnNullable - definitely allows NULL values
columnNullableUnknown - nullability unknown
REMARKS String => comment describing column (may be null)
COLUMN_DEF String => default value for the column, which should be interpreted as a string when the value is enclosed in single quotes (may be null)
SQL_DATA_TYPE int => unused
SQL_DATETIME_SUB int => unused
CHAR_OCTET_LENGTH int => for char types the maximum number of bytes in the column
ORDINAL_POSITION int => index of column in table (starting at 1)
IS_NULLABLE String => ISO rules are used to determine the nullability for a column.
YES --- if the column can include NULLs
NO --- if the column cannot include NULLs
empty string --- if the nullability for the column is unknown
SCOPE_CATALOG String => catalog of table that is the scope of a reference attribute (null if DATA_TYPE isn't REF)
SCOPE_SCHEMA String => schema of table that is the scope of a reference attribute (null if the DATA_TYPE isn't REF)
SCOPE_TABLE String => table name that this the scope of a reference attribute (null if the DATA_TYPE isn't REF)
SOURCE_DATA_TYPE short => source type of a distinct type or user-generated Ref type, SQL type from java.sql.Types (null if DATA_TYPE isn't DISTINCT or user-generated REF)
IS_AUTOINCREMENT String => Indicates whether this column is auto incremented
YES --- if the column is auto incremented
NO --- if the column is not auto incremented
empty string --- if it cannot be determined whether the column is auto incremented
IS_GENERATEDCOLUMN String => Indicates whether this is a generated column
YES --- if this a generated column
NO --- if this not a generated column
empty string --- if it cannot be determined whether this is a generated column
*/
String dataType = rs.getString("DATA_TYPE");
f.setSqlType(new Integer(dataType).intValue());//如：java.sql.Types.INTEGER
String type = rs.getString("TYPE_NAME");//如:BIGINT
f.setTypeName(lowerCase(type));
String position = rs.getString("ORDINAL_POSITION");//在表中的位置
f.setPosition(position);
String size = rs.getString("COLUMN_SIZE");//用户定义的字段长度
f.setSize(size);
String bufferLength = rs.getString("BUFFER_LENGTH");//字段缓冲区大小
f.setBufferLength(bufferLength);
String decim