使用teradata系統表獲取列類型

Question

我想從teradata系統表（如dbc.columns）獲取實際列類型。

該表具有列columntype，但它不提供實際的數據類型。

我可以輸出與

select type(columnname) from table 
output: varchar2(20) 

但也有1000臺和50000列。請建議一些查詢，可以給我從元數據本身列的實際列類型

Answer 1

對於視圖columntype將爲NULL，因爲它已在運行時解析。

對於單個表格，您可以執行HELP COLUMN viewname。*;來獲取實際的數據類型。

順便說一句，有沒有這樣的類型像VARCHAR2在Teradata的，這是甲骨文:-)

編輯： 好像你想要一個列的完整定義。這是一個SQL UDF返回你的SHOW表中找到相同的信息（如果TD14.10覆蓋我不是舒爾，我也沒有檢查，還）：

REPLACE FUNCTION DataTypeString 
(
    ColumnType CHAR(2), 
    ColumnLength INT, 
    DecimalTotalDigits SMALLINT, 
    DecimalFractionalDigits SMALLINT, 
    CharType SMALLINT, 
    ColumnUDTName VARCHAR(128) CHARACTER SET UNICODE 
) 
RETURNS VARCHAR(60) 
LANGUAGE SQL 
CONTAINS SQL 
DETERMINISTIC 
SQL SECURITY DEFINER 
COLLATION INVOKER 
INLINE TYPE 1 
RETURN 
    CASE ColumnType 
    WHEN 'BF' THEN 'BYTE('   || TRIM(CAST(ColumnLength AS INTEGER)) || ')' 
    WHEN 'BV' THEN 'VARBYTE('   || TRIM(CAST(ColumnLength AS INTEGER)) || ')' 
    WHEN 'CF' THEN 'CHAR('   || TRIM(CAST(ColumnLength AS INTEGER)) || ')' 
    WHEN 'CV' THEN 'VARCHAR('   || TRIM(CAST(ColumnLength AS INTEGER)) || ')' 
    WHEN 'D ' THEN 'DECIMAL('   || TRIM(DecimalTotalDigits) || ',' 
             || TRIM(DecimalFractionalDigits) || ')' 
    WHEN 'DA' THEN 'DATE' 
    WHEN 'F ' THEN 'FLOAT' 
    WHEN 'I1' THEN 'BYTEINT' 
    WHEN 'I2' THEN 'SMALLINT' 
    WHEN 'I8' THEN 'BIGINT' 
    WHEN 'I ' THEN 'INTEGER' 
    WHEN 'AT' THEN 'TIME('   || TRIM(DecimalFractionalDigits) || ')' 
    WHEN 'TS' THEN 'TIMESTAMP('  || TRIM(DecimalFractionalDigits) || ')' 
    WHEN 'TZ' THEN 'TIME('   || TRIM(DecimalFractionalDigits) || ')' || ' WITH TIME ZONE' 
    WHEN 'SZ' THEN 'TIMESTAMP('  || TRIM(DecimalFractionalDigits) || ')' || ' WITH TIME ZONE' 
    WHEN 'YR' THEN 'INTERVAL YEAR(' || TRIM(DecimalTotalDigits) || ')' 
    WHEN 'YM' THEN 'INTERVAL YEAR(' || TRIM(DecimalTotalDigits) || ')'  || ' TO MONTH' 
    WHEN 'MO' THEN 'INTERVAL MONTH(' || TRIM(DecimalTotalDigits) || ')' 
    WHEN 'DY' THEN 'INTERVAL DAY(' || TRIM(DecimalTotalDigits) || ')' 
    WHEN 'DH' THEN 'INTERVAL DAY(' || TRIM(DecimalTotalDigits) || ')'  || ' TO HOUR' 
    WHEN 'DM' THEN 'INTERVAL DAY(' || TRIM(DecimalTotalDigits) || ')'  || ' TO MINUTE' 
    WHEN 'DS' THEN 'INTERVAL DAY(' || TRIM(DecimalTotalDigits) || ')'  || ' TO SECOND(' 
             || TRIM(DecimalFractionalDigits) || ')' 
    WHEN 'HR' THEN 'INTERVAL HOUR(' || TRIM(DecimalTotalDigits) || ')' 
    WHEN 'HM' THEN 'INTERVAL HOUR(' || TRIM(DecimalTotalDigits) || ')'  || ' TO MINUTE' 
    WHEN 'HS' THEN 'INTERVAL HOUR(' || TRIM(DecimalTotalDigits) || ')'  || ' TO SECOND(' 
             || TRIM(DecimalFractionalDigits) || ')' 
    WHEN 'MI' THEN 'INTERVAL MINUTE(' || TRIM(DecimalTotalDigits) || ')' 
    WHEN 'MS' THEN 'INTERVAL MINUTE(' || TRIM(DecimalTotalDigits) || ')'  || ' TO SECOND(' 
             || TRIM(DecimalFractionalDigits) || ')' 
    WHEN 'SC' THEN 'INTERVAL SECOND(' || TRIM(DecimalTotalDigits) || ',' 
             || TRIM(DecimalFractionalDigits) || ')' 
    WHEN 'BO' THEN 'BLOB('   || TRIM(CAST(ColumnLength AS INTEGER)) || ')' 
    WHEN 'CO' THEN 'CLOB('   || TRIM(CAST(ColumnLength AS INTEGER)) || ')' 

    WHEN 'PD' THEN 'PERIOD(DATE)'  
    WHEN 'PM' THEN 'PERIOD(TIMESTAMP('|| TRIM(DecimalFractionalDigits) || ')' || ' WITH TIME ZONE' 
    WHEN 'PS' THEN 'PERIOD(TIMESTAMP('|| TRIM(DecimalFractionalDigits) || '))' 
    WHEN 'PT' THEN 'PERIOD(TIME('  || TRIM(DecimalFractionalDigits) || '))' 
    WHEN 'PZ' THEN 'PERIOD(TIME('  || TRIM(DecimalFractionalDigits) || '))' || ' WITH TIME ZONE' 
    WHEN 'UT' THEN COALESCE(ColumnUDTName, '<Unknown> ' || ColumnType) 

    WHEN '++' THEN 'TD_ANYTYPE' 
    WHEN 'N' THEN 'NUMBER('   || CASE WHEN DecimalTotalDigits = -128 THEN '*' ELSE TRIM(DecimalTotalDigits) END 
             || CASE WHEN DecimalFractionalDigits IN (0, -128) THEN '' ELSE ',' || TRIM(DecimalFractionalDigits) END 
             || ')' 
    WHEN 'A1' THEN COALESCE('SYSUDTLIB.' || ColumnUDTName, '<Unknown> ' || ColumnType) 
    WHEN 'AN' THEN COALESCE('SYSUDTLIB.' || ColumnUDTName, '<Unknown> ' || ColumnType) 

    ELSE '<Unknown> ' || ColumnType 
    END 
    || CASE 
     WHEN ColumnType IN ('CV', 'CF', 'CO') 
     THEN CASE CharType 
       WHEN 1 THEN ' CHARACTER SET LATIN' 
       WHEN 2 THEN ' CHARACTER SET UNICODE' 
       WHEN 3 THEN ' CHARACTER SET KANJISJIS' 
       WHEN 4 THEN ' CHARACTER SET GRAPHIC' 
       WHEN 5 THEN ' CHARACTER SET KANJI1' 
       ELSE '' 
      END 
     ELSE '' 
     END 
; 

Answer 2

我發現這個說法

SELECT 
DATABASENAME, TABLENAME, COLUMNNAME, TRIM(COLUMNTYPE)||'('||TRIM(COLUMNNUM)||')' 
FROM (
    SELECT DATABASENAME, TABLENAME, COLUMNNAME, 
    CASE 
    WHEN COLUMNTYPE='CF' THEN 'CHAR' 
    WHEN COLUMNTYPE='CV' THEN 'VARCHAR' 
    WHEN COLUMNTYPE='D' THEN 'DECIMAL' 
    WHEN COLUMNTYPE='TS' THEN 'TIMESTAMP'  
    WHEN COLUMNTYPE='I' THEN 'INTEGER' 
    WHEN COLUMNTYPE='I2' THEN 'SMALLINT' 
    WHEN COLUMNTYPE='DA' THEN 'DATE' 
    END AS COLUMNTYPE, 
    CASE 
    WHEN COLUMNTYPE='CF' THEN COLUMNLENGTH 
    WHEN COLUMNTYPE='CV' THEN COLUMNLENGTH 
    WHEN COLUMNTYPE='D' THEN (DECIMALTOTALDIGITS||','||DECIMALFRACTIONALDIGITS) 
    WHEN COLUMNTYPE='TS' THEN COLUMNLENGTH  
    WHEN COLUMNTYPE='I' THEN DECIMALTOTALDIGITS 
    WHEN COLUMNTYPE='I2' THEN DECIMALTOTALDIGITS 
    WHEN COLUMNTYPE='DA' THEN NULL 
    END AS COLUMNNUM 
    FROM DBC.COLUMNS 
    WHERE DATABASENAME='your database' 
) TBL 

Answer 3

去通過Retrieving column and other metadata information in Teradata我建議取出從DBC表的表和列的名稱，然後建立一個「簡單的腳本」獲取所有的信息。我對TD沒有任何線索，但是從Quick Reference開始，創建一個可以動態獲取結果並將其插入到自己的表中的循環應該不會太困難。

最後一個良好的情況下提出的光標=）