Oracle database table structure turn MySQL table structure

This function from the department chiefs Jie, use this
when you need to migrate Oracle database tables to MySQL, MySQL need to organize construction of the table statement, manual sorting is too much trouble, especially finishing column notes the statement. At this point you can use the following function to automatically generate versions of MySQL statements.

parameter:

1, need to convert the table name;
2, contains "already exists then delete the statement" (DROP TABLE IF EXISTS), included by default

Instructions:

`SELECT F_LIMS_GET_SQL_FOR_MYSQL('T_LIMS_EQUIPMENT') FROM DUAL;

or

SELECT F_LIMS_GET_SQL_FOR_MYSQL('T_LIMS_EQUIPMENT',0) FROM DUAL;`

A copy of the query results, can be executed in the MySQL library.

Function is as follows:

```sql
CREATE OR REPLACE FUNCTION F_LIMS_GET_SQL_FOR_MYSQL(PI_TABLENAME IN VARCHAR2,
                                                    PI_ISDROP    IN INTEGER := 1)
  RETURN CLOB IS
  V_TABLENAME         VARCHAR(100);
  V_RET_SQL           VARCHAR2(4000);
  V_SQL_HEADER        VARCHAR2(1000);
  V_SQL_BODY          CLOB;
  V_SQL_INDEX         VARCHAR2(4000);
  V_SQL_TABLE_COMMENT VARCHAR(400);
  V_SQL_PK_COL_LIST   VARCHAR(1000);
  -- 根据当前数据库和表名，生成mysql建表语句
BEGIN
  -- 表名统一为大写
  SELECT UPPER(PI_TABLENAME) INTO V_TABLENAME FROM DUAL;

  SELECT MAX(T.COMMENTS)
    INTO V_SQL_TABLE_COMMENT
    FROM USER_TAB_COMMENTS T
   WHERE T.TABLE_NAME = V_TABLENAME;

  SELECT MAX(WM_CONCAT('`' || A.COLUMN_NAME || '` '))
    INTO V_SQL_PK_COL_LIST
    FROM USER_CONS_COLUMNS A, USER_CONSTRAINTS B
   WHERE A.CONSTRAINT_NAME = B.CONSTRAINT_NAME
     AND B.CONSTRAINT_TYPE = 'P'
     AND A.TABLE_NAME = V_TABLENAME
   GROUP BY A.TABLE_NAME;

  V_SQL_HEADER := '-- ' || V_SQL_TABLE_COMMENT || ' 建表语句' || CHR(13);

  IF PI_ISDROP = 1 THEN
    V_SQL_HEADER := V_SQL_HEADER || 'DROP TABLE IF EXISTS `' || V_TABLENAME || '`;' ||
                    CHR(13);
  END IF;
  V_SQL_HEADER := V_SQL_HEADER || 'CREATE TABLE `' || V_TABLENAME || '`  (';

  -- 表列信息
  SELECT WM_CONCAT(CHR(13) || '`' || T.COLUMN_NAME || '` ' ||
                   (CASE
                      WHEN T.DATA_TYPE = 'VARCHAR2' OR T.DATA_TYPE = 'NVARCHAR2' THEN
                       'VARCHAR(' || T.DATA_LENGTH || ')'
                      WHEN T.DATA_TYPE = 'DATE' THEN
                       'DATETIME'
                      WHEN T.DATA_TYPE = 'CLOB' THEN
                       'MEDIUMTEXT'
                      WHEN T.DATA_TYPE = 'NUMBER' THEN
                       'DECIMAL'
                      WHEN T.COLUMN_NAME = 'ID' THEN
                       'VARCHAR(32)'
                      ELSE
                       T.DATA_TYPE
                    END) || DECODE(T.NULLABLE, 'N', ' NOT NULL ', '') ||
                   ' COMMENT ''' || TC.COMMENTS || '''')
    INTO V_SQL_BODY
    FROM USER_TAB_COLUMNS T
    LEFT JOIN USER_COL_COMMENTS TC
      ON T.TABLE_NAME = TC.TABLE_NAME
     AND T.COLUMN_NAME = TC.COLUMN_NAME
   WHERE T.TABLE_NAME = V_TABLENAME
   ORDER BY T.COLUMN_ID;

  IF V_SQL_PK_COL_LIST IS NOT NULL THEN
    V_SQL_BODY := V_SQL_BODY || ' ,' || CHR(13) || ' PRIMARY KEY (' ||
                  V_SQL_PK_COL_LIST || ')  ';
  END IF;

  -- 表备注
  V_SQL_BODY := V_SQL_BODY || CHR(13) || ') COMMENT = ''' ||
                V_SQL_TABLE_COMMENT || ''';' || CHR(13);

  -- 唯一索引 
  SELECT (WM_CONCAT('@ALTER TABLE `' || A.TABLE_NAME ||
                    '` ADD UNIQUE INDEX (' ||
                    WM_CONCAT('`' || A.COLUMN_NAME || '`') || ');@'))
    INTO V_SQL_INDEX
    FROM USER_CONS_COLUMNS A, USER_CONSTRAINTS B
   WHERE A.CONSTRAINT_NAME = B.CONSTRAINT_NAME
     AND B.CONSTRAINT_TYPE = 'U'
     AND A.TABLE_NAME = V_TABLENAME
   GROUP BY A.TABLE_NAME, A.CONSTRAINT_NAME;

  IF V_SQL_INDEX IS NOT NULL THEN
    V_SQL_INDEX := REPLACE(REPLACE(V_SQL_INDEX, '@,@', CHR(13)), '@', '');
    V_SQL_INDEX := '-- 创建索引' || CHR(13) || V_SQL_INDEX;
  END IF;

  RETURN V_SQL_HEADER || V_SQL_BODY || V_SQL_INDEX;
END;
/