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teradata_to_exasol.sql
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teradata_to_exasol.sql
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create schema if not exists database_migration;
/*
This script will generate create schema, create table and create import statements
to load all needed data from a teradata database. Automatic datatype conversion is
applied whenever needed. Additionally the migration can be checked via generic metrics.
For that a checking table will be created and loaded for each individual table being migrated.
The checking table will be created in the same schema with the same name adding '_MIG_CHK' as a suffix.
A summary table for all the checking tables of a specific schema will be created in the database migration schema with the name of the migrated schema adding '_MIG_CHK' as a suffix.
Querying the summary tables will help you to identify deviations easily.
Feel free to adjust it.
*/
--/
create or replace script database_migration.TERADATA_TO_EXASOL(
CONNECTION_NAME --name of the database connection inside exasol -> e.g. teradata_db
,IDENTIFIER_CASE_INSENSITIVE --true if identifiers should be stored case-insensitiv (will be stored upper_case)
,SCHEMA_FILTER --filter for the schemas to generate and load (except system schemas) -> '%' to load all
,TABLE_FILTER --filter for the tables to generate and load -> '%' to load all
,CHECK_MIGRATION --boolean flag to create and load checking tables with standardized metrics to identify deviations
) RETURNS TABLE
AS
exa_upper_begin=''
exa_upper_end=''
if IDENTIFIER_CASE_INSENSITIVE == true then
exa_upper_begin='upper('
exa_upper_end=')'
end
check_control = 0
if CHECK_MIGRATION then
check_control = 1
end
res = query([[
with vv_columns as (
select ]]..exa_upper_begin..[["table_schema"]]..exa_upper_end..[[ as "exa_table_schema",
]]..exa_upper_begin..[["table_name"]]..exa_upper_end..[[ as "exa_table_name",
]]..exa_upper_begin..[["column_name"]]..exa_upper_end..[[ as "exa_column_name",
'"' || "column_name" || '"' as "column_name_delimited",
tableList.*
from (
import from jdbc at ]]..CONNECTION_NAME..[[
statement '
select trim(c.DatabaseName) as table_schema,
trim(c.TableName) as table_name,
ColumnName as column_name,
ColumnId as ordinal_position,
trim(ColumnType) as data_type,
cast(case when ColumnType in (''CF'', ''CV'') then substr(ColumnFormat, 3, length(ColumnFormat)-3) else ColumnLength end as integer) as character_maximum_length,
DecimalTotalDigits as numeric_precision,
DecimalFractionalDigits as numeric_scale,
DecimalFractionalDigits as datetime_precision,
case when nullable = ''Y'' then 1 when nullable = ''N'' then 0 end as nullable
from DBC.ColumnsV c
join DBC.TablesV t
on c.databaseName=t.DatabaseName
AND c.TableName=t.TableName
AND TableKind=''T''
where table_schema not in (''All'', ''Crashdumps'', ''DBC'', ''dbcmngr'',
''Default'', ''External_AP'', ''EXTUSER'', ''LockLogShredder'', ''PUBLIC'',
''Sys_Calendar'', ''SysAdmin'', ''SYSBAR'', ''SYSJDBC'', ''SYSLIB'',
''SystemFe'', ''SYSUDTLIB'', ''SYSUIF'', ''TD_SERVER_DB'', ''TDStats'',
''TD_SYSGPL'', ''TD_SYSXML'', ''TDMaps'', ''TDPUSER'', ''TDQCD'',
''tdwm'', ''SQLJ'', ''TD_SYSFNLIB'', ''SYSSPATIAL'')
AND table_schema like '']]..SCHEMA_FILTER..[[''
AND table_name like '']]..TABLE_FILTER..[[''
') as tableList
)
, vv_primary_keys_raw as (
select ]]..exa_upper_begin..[["table_schema"]]..exa_upper_end..[[ as "exa_table_schema",
]]..exa_upper_begin..[["table_name"]]..exa_upper_end..[[ as "exa_table_name",
]]..exa_upper_begin..[["column_name"]]..exa_upper_end..[[ as "exa_column_name",
"table_schema" as "table_schema",
"table_name" as "table_name",
"column_name" as "column_name",
"column_position" as "column_position"
from (
import from jdbc at ]]..CONNECTION_NAME..[[
statement '
SELECT DatabaseName as table_schema,
TableName as table_name,
ColumnName as column_name,
ColumnPosition as column_position
FROM DBC.IndicesV
WHERE UniqueFlag = ''Y'' AND IndexType IN (''K'')
and table_schema not in (''All'', ''Crashdumps'', ''DBC'', ''dbcmngr'',
''Default'', ''External_AP'', ''EXTUSER'', ''LockLogShredder'', ''PUBLIC'',
''Sys_Calendar'', ''SysAdmin'', ''SYSBAR'', ''SYSJDBC'', ''SYSLIB'',
''SystemFe'', ''SYSUDTLIB'', ''SYSUIF'', ''TD_SERVER_DB'', ''TDStats'',
''TD_SYSGPL'', ''TD_SYSXML'', ''TDMaps'', ''TDPUSER'', ''TDQCD'',
''tdwm'', ''SQLJ'', ''TD_SYSFNLIB'', ''SYSSPATIAL'')
and table_schema like '']]..SCHEMA_FILTER..[[''
and table_name like '']]..TABLE_FILTER..[[''
'
) as primarykeylist
)
,vv_foreign_keys_raw as (
select ]]..exa_upper_begin..[["ChildDB"]]..exa_upper_end..[[ as "exa_table_schema",
]]..exa_upper_begin..[["ChildTable"]]..exa_upper_end..[[ as "exa_table_name",
]]..exa_upper_begin..[["ChildKeyColumn"]]..exa_upper_end..[[ as "exa_foreign_key_column",
]]..exa_upper_begin..[["ParentDB"]]..exa_upper_end..[[ as "exa_referenced_table_schema",
]]..exa_upper_begin..[["ParentTable"]]..exa_upper_end..[[ as "exa_referenced_table_name"
from (
import from jdbc at ]]..CONNECTION_NAME..[[
statement '
SELECT ChildDB,
ChildTable,
ChildKeyColumn,
ParentDB ,
ParentTable
FROM DBC.All_RI_ChildrenV
WHERE ChildDB NOT IN (''All'', ''Crashdumps'', ''DBC'', ''dbcmngr'',
''Default'', ''External_AP'', ''EXTUSER'', ''LockLogShredder'', ''PUBLIC'',
''Sys_Calendar'', ''SysAdmin'', ''SYSBAR'', ''SYSJDBC'', ''SYSLIB'',
''SystemFe'', ''SYSUDTLIB'', ''SYSUIF'', ''TD_SERVER_DB'', ''TDStats'',
''TD_SYSGPL'', ''TD_SYSXML'', ''TDMaps'', ''TDPUSER'', ''TDQCD'',
''tdwm'', ''SQLJ'', ''TD_SYSFNLIB'', ''SYSSPATIAL'')
and ChildDB like '']]..SCHEMA_FILTER..[[''
and ChildTable like '']]..TABLE_FILTER..[[''
'
)
),
vv_create_schemas as(
SELECT 'create schema if not exists "' || "exa_table_schema" || '";' as sql_text
from vv_columns
group by "exa_table_schema"
order by "exa_table_schema"
)
,vv_create_tables as (
select 'create or replace table "' || "exa_table_schema" || '"."' || "exa_table_name" || '" (' ||
group_concat(
case
when "data_type" = 'PD' then -- a teradata PERIOD(DATE) is splitted into the beginning and end DATE
'"' || "exa_column_name" || '_BEGINNING " DATE,' ||
'"' || "exa_column_name" || '_END" DATE'
when "data_type" in ('PS', 'PM', 'PT', 'PZ') then -- a teradata PERIOD(TIMESTAMP) is splitted into the beginning and end TIMESTAMP
'"' || "exa_column_name" || '_BEGINNING " TIMESTAMP,' ||
'"' || "exa_column_name" || '_END" TIMESTAMP'
else
'"' || "exa_column_name" || '" '
end ||
case
when "data_type" = 'PD' then '' --Period is already splitted into two dates before
when "data_type" in ('PS', 'PM', 'PT', 'PZ') then '' --Period is already splitted into two timestamps before
when "data_type" = 'DA' then 'DATE'
when "data_type" in ('BF', 'BO', 'BV') then 'VARCHAR(100)' --binary data types like BYTE, VARBYTE, BLOB are not supported then
when "data_type" = 'D' then
case
when "numeric_precision" is null or "numeric_precision" > 36 then
'DOUBLE'
else 'decimal(' || "numeric_precision" || ',' ||
case when ("numeric_scale" > "numeric_precision") then
"numeric_precision"
else
case
when "numeric_scale" < 0 then
0
else
"numeric_scale"
end
end || ')'
end
when "data_type" = 'TS' then 'TIMESTAMP'
when "data_type" = 'TZ' then 'TIMESTAMP'
when "data_type" = 'SZ' then 'TIMESTAMP'
when "data_type" = 'CF' then
case
when nvl("character_maximum_length",2000) > 2000 then
'varchar(' ||
nvl("character_maximum_length",2000) || ')'
else
'char(' ||
nvl("character_maximum_length",2000) || ')'
end
when "data_type" = 'I1' then 'DECIMAL(9)'
when "data_type" = 'I2' then 'DECIMAL(9)'
when "data_type" = 'I8' then 'DECIMAL(19)' --maybe 18 but can result in errors while importing
when "data_type" = 'AT' then 'TIMESTAMP'
when "data_type" = 'F' then 'DOUBLE'
when "data_type" in( 'CV' , 'JN') then --Varchar and JSON
'varchar(' || case when nvl("character_maximum_length",2000000) > 2000000 then
2000000
else
nvl("character_maximum_length",2000000)
end || ')'
when "data_type" = 'I' then 'DECIMAL(10)' --maybe 9 but can result in errors while importing
when "data_type" = 'N' then --Number type
case when "numeric_precision" is null or "numeric_precision" > 36 or "numeric_precision" = -128 then
'DOUBLE'
else 'decimal(' || "numeric_precision" || ',' ||
case when ("numeric_scale" > "numeric_precision")
then "numeric_precision" else
case when "numeric_scale" < 0 then
0
else "numeric_scale"
end
end || ')'
end
when "data_type" = 'YR' then --INTERVAL YEAR
'INTERVAL YEAR (' || "numeric_precision" || ') TO MONTH'
when "data_type" = 'YM' then --INTERVAL YEAR TO MONTH
'INTERVAL YEAR (' || "numeric_precision" || ') TO MONTH'
when "data_type" = 'MO' then --INTERVAL MONTH
'INTERVAL YEAR (4) TO MONTH'
when "data_type" = 'DY' then --INTERVAL DAY
'INTERVAL DAY (4) TO SECOND'
when "data_type" = 'DH' then --INTERVAL DAY TO HOUR
'INTERVAL DAY (4) TO SECOND'
when "data_type" = 'DM' then --INTERVAL DAY TO MINUTE
'INTERVAL DAY (4) TO SECOND'
when "data_type" = 'DS' then --INTERVAL DAY TO SECOND
'INTERVAL DAY (4) TO SECOND (' || "numeric_scale" || ')'
when "data_type" = 'HR' then --INTERVAL HOUR
'INTERVAL DAY (4) TO SECOND'
when "data_type" = 'HM' then --INTERVAL HOUR TO MINUTE
'INTERVAL DAY (4) TO SECOND '
when "data_type" = 'HS' then --INTERVAL HOUR TO SECOND
'INTERVAL DAY (4) TO SECOND (' || "numeric_scale" || ')'
when "data_type" = 'MI' then --INTERVAL MINUTE
'INTERVAL DAY (4) TO SECOND'
when "data_type" = 'MS' then --INTERVAL MINUTE TO SECOND
'INTERVAL DAY (4) TO SECOND (' || "numeric_scale" || ')'
when "data_type" = 'SC' then --INTERVAL SECOND
'INTERVAL DAY (4) TO SECOND (' || "numeric_scale" || ')'
when "data_type" in ('A1','AN') then --ARRAY Datatype
'VARCHAR(64000)'
else '/*UNKNOWN_DATATYPE:' || "data_type" || '*/ varchar(2000000)'
end || case when "nullable" = 0 then ' NOT NULL ' else '' end
order by "ordinal_position") || ');' as sql_text
from vv_columns
group by "exa_table_schema", "exa_table_name"
order by "exa_table_schema","exa_table_name"
)
, vv_primary_keys as (
select 'ALTER TABLE "' || "exa_table_schema" || '"."' || "exa_table_name" || '" ADD CONSTRAINT PRIMARY KEY (' ||
group_concat('"'|| "exa_column_name" || '"' order by "column_position") || ') ;' as sql_text
from vv_primary_keys_raw
group by "exa_table_schema", "exa_table_name"
order by "exa_table_schema","exa_table_name"
), vv_foreign_keys as (
select 'ALTER TABLE "' || "exa_table_schema" || '"."' || "exa_table_name" ||
'" ADD FOREIGN KEY (' || '"'|| "exa_foreign_key_column" || '") REFERENCES "' || "exa_referenced_table_schema" || '"."' || "exa_referenced_table_name" || '" DISABLE ;' as sql_text
from vv_foreign_keys_raw
order by "exa_table_schema","exa_table_name"
)
, vv_imports as (
select 'import into "' || "exa_table_schema" || '"."' || "exa_table_name" || '" from jdbc at ]]..CONNECTION_NAME..[[ statement ''select ' || group_concat(
case
when "data_type" = 'DA' then "column_name_delimited"
when "data_type" = 'D' then "column_name_delimited"
when "data_type" = 'TS' then "column_name_delimited"
when "data_type" = 'CF' then "column_name_delimited"
when "data_type" = 'I1' then "column_name_delimited"
when "data_type" = 'I2' then "column_name_delimited"
when "data_type" = 'I8' then "column_name_delimited"
when "data_type" = 'AT' then "column_name_delimited"
when "data_type" = 'F' then "column_name_delimited"
when "data_type" = 'CV' then "column_name_delimited"
when "data_type" = 'I' then "column_name_delimited"
when "data_type" = 'N' then "column_name_delimited"
when "data_type" in ('A1','AN') then 'cast(' || "column_name_delimited" || ' as varchar(64000)) ' --array datatypes are casted to a varchar in Teradata
when "data_type" in ('BF', 'BO', 'BV') then '''''NOT SUPPORTED''''' --binary data types (BYTE, VARBYTE, BLOB) are not supported
when "data_type" = 'JN' then 'CAST(' || "column_name_delimited" || ' AS CLOB ) ' --json (max length in Exasol is 2000000 as it is stored as varchar)
when "data_type" = 'PD' then 'BEGIN('|| "column_name_delimited" || ') , END(' || "column_name_delimited" || ')' --Period(Date) split into begin and end date
when "data_type" in ('PS', 'PM') then 'CAST( BEGIN('|| "column_name_delimited" || ') AS TIMESTAMP ) , CAST ( END(' || "column_name_delimited" || ') AS TIMESTAMP ) ' --Period(Timestamp) split into begin and end timestamp
when "data_type" in ('PT', 'PZ') then 'CAST( BEGIN('|| "column_name_delimited" || ') AS TIME ) , CAST ( END(' || "column_name_delimited" || ') AS TIME ) ' --Period(Time) split into begin and end time
when "data_type" = 'TZ' then 'cast(' || "column_name_delimited" || ' AS TIME)' --time with time zone
when "data_type" = 'SZ' then 'cast(' || "column_name_delimited" || ' AS TIMESTAMP)' --timestamp with time zone
when "data_type" = 'YR' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL YEAR TO MONTH ) AS VARCHAR(50))' --Interval Year
when "data_type" = 'YM' then 'cast('|| "column_name_delimited" || ' AS VARCHAR(50) )' --Interval Year to Month
when "data_type" = 'MO' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL YEAR TO MONTH ) AS VARCHAR(50))' --Interval Month
when "data_type" = 'DY' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL DAY (4) TO SECOND) AS VARCHAR(50)) ' --Interval Day
when "data_type" = 'DH' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL DAY (4) TO SECOND) AS VARCHAR(50)) ' --Interval Day to hour
when "data_type" = 'DM' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL DAY (4) TO SECOND) AS VARCHAR(50)) ' --Interval Day to minute
when "data_type" = 'DS' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL DAY (4) TO SECOND (' || "numeric_scale" || ')) AS VARCHAR(50)) ' --Interval day to second
when "data_type" = 'HR' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL DAY (4) TO SECOND) AS VARCHAR(50)) ' --Interval Hour
when "data_type" = 'HM' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL DAY (4) TO SECOND) AS VARCHAR(50)) ' --Interval Day to minute
when "data_type" = 'HS' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL DAY (4) TO SECOND (' || "numeric_scale" || ')) AS VARCHAR(50)) ' --Interval day to second
when "data_type" = 'MI' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL DAY (4) TO SECOND) AS VARCHAR(50)) ' --Interval Minute
when "data_type" = 'MS' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL DAY (4) TO SECOND (' || "numeric_scale" || ')) AS VARCHAR(50)) ' --Interval minute to second
when "data_type" = 'SC' then 'cast(cast('|| "column_name_delimited" || ' AS INTERVAL DAY (4) TO SECOND (' || "numeric_scale" || ')) AS VARCHAR(50)) ' --Interval Second
else "column_name_delimited"
end
order by "ordinal_position") || ' from ' || "table_schema"|| '.' || "table_name"|| ''';' as sql_text
from vv_columns
group by "exa_table_schema","exa_table_name", "table_schema","table_name"
order by "exa_table_schema","exa_table_name", "table_schema","table_name"
)
, vv_checks_expr as (
select "db_system", c."exa_table_schema", c."exa_table_name", c."exa_column_name", c."column_name_delimited", c."table_schema", c."table_name", c."ordinal_position", c."data_type", c."nullable",
count(case when p."exa_column_name" is not null then 1 end) over (partition by c."exa_table_schema", c."exa_table_name") as "cnt_pk",
case when p."exa_column_name" is not null then true else false end "is_pk",
p."column_position" as "column_position_pk",
"metric_id",
'DATABASE_MIGRATION' as "metric_schema",
c."exa_table_name" || '_MIG_CHK' as "metric_table",
case when c."ordinal_position" = 1 and "metric_id" = 0 then 'cast(count(*) as decimal(36,0))'
when "nullable" = 1 and "metric_id" = 1 then 'cast(count(case when ' || case when "db_system" = 'Exasol' then '"' || c."exa_column_name" || '"' else c."column_name_delimited" end || ' is null then 1 end) as decimal(36,0))'
when c."data_type" in ( 'DA', --DATE
'AT', --TIME
'TZ', --TIME WITH TIME ZONE
'TS', --TIMESTAMP
'SZ', --TIMESTAMP WITH TIME ZONE
'I', --INTEGER
'I1', --BYTEINT
'I2', --SMALLINT
'I8', --BIGINT
'F', --DOUBLE PRECISION
'N', --NUMBER
'D' --DECIMAL
) then
case when "metric_id" = 2 then
case when c."data_type" in ('I', 'I1','I2','I8','F','N','D') then 'cast(' end ||
'min(' || case when "db_system" = 'Exasol' then '"' || c."exa_column_name" || '"' else c."column_name_delimited" end || ')' ||
case when c."data_type" in ('I1', 'I2', 'I8', 'I') then ' as decimal(20,0))'
when c."data_type" = 'F' or c."numeric_precision" > 36 or c."numeric_precision" = -128 then ' as double precision)'
when c."data_type" in ('N', 'D') and c."numeric_precision" > 0 and c."numeric_scale" >= 0 then ' as decimal(' || c."numeric_precision" || ', ' || c."numeric_scale" || '))'
end
when "metric_id" = 3 then
case when c."data_type" in ('I', 'I1','I2','I8','F','N','D') then 'cast(' end ||
'max(' || case when "db_system" = 'Exasol' then '"' || c."exa_column_name" || '"' else c."column_name_delimited" end || ')' ||
case when c."data_type" in ('I1', 'I2', 'I8', 'I') then ' as decimal(20,0))'
when c."data_type" = 'F' or c."numeric_precision" > 36 or c."numeric_precision" = -128 then ' as double precision)'
when c."data_type" in ('N', 'D') and c."numeric_precision" > 0 and c."numeric_scale" >= 0 then ' as decimal(' || c."numeric_precision" || ', ' || c."numeric_scale" || '))'
end
when "metric_id" = 4 then
'cast(count(distinct(' || case when "db_system" = 'Exasol' then '"' || c."exa_column_name" || '"' else c."column_name_delimited" end || ')) as decimal(36,0))'
when "metric_id" = 5 then
case when c."data_type" in ('D', 'I1', 'I2', 'I8', 'F', 'I', 'N') then
'cast(avg(cast(' || case when "db_system" = 'Exasol' then '"' || c."exa_column_name" || '"' else c."column_name_delimited" end || ' as double precision)) as double precision)' --avoiding numeric overflow by casting the column first , second cast is to make sure the data types match after the import
end
end
when c."data_type" in ( 'PD', --PERIOD(DATE)
'PT', --PERIOD(TIME(n))
'PZ', --PERIOD(TIME(n) WITH TIME ZONE)
'PS', --PERIOD(TIMESTAMP(n))
'PM' --PERIOD(TIMESTAMP(n) WITH TIME ZONE)
) then
case when "db_system" = 'Exasol' then
case when "metric_id" = 2 then 'min("' || c."exa_column_name" || '_BEGINNING")'
when "metric_id" = 3 then 'max("' || c."exa_column_name" || '_BEGINNING")'
when "metric_id" = 4 then 'min("' || c."exa_column_name" || '_END")'
when "metric_id" = 5 then 'max("' || c."exa_column_name" || '_END")'
when "metric_id" = 6 then 'cast(count(distinct("' || c."exa_column_name" || '_BEGINNING", "' || c."exa_column_name" || '_END")) as decimal(36,0))'
end
when "db_system" = 'Teradata' then
case when "metric_id" = 2 then 'min(begin(' || c."column_name_delimited" || '))'
when "metric_id" = 3 then 'max(begin(' || c."column_name_delimited" || '))'
when "metric_id" = 4 then 'min(end(' || c."column_name_delimited" || '))'
when "metric_id" = 5 then 'max(end(' || c."column_name_delimited" || '))'
when "metric_id" = 6 then 'cast(count(distinct(' || c."column_name_delimited" || ')) as decimal(36,0))'
end
end
when c."data_type" in ( 'CF', --CHARACTER (fixed)
'CV' --CHARACTER (varying)
) then
case when not(c."data_type" = 'CF' and "character_maximum_length" > 2000) then
case when "metric_id" = 2 then 'cast(min(length(' || case when "db_system" = 'Exasol' then '"' || c."exa_column_name" || '"' else c."column_name_delimited" end || ')) as decimal(36,0))'
when "metric_id" = 3 then 'cast(max(length(' || case when "db_system" = 'Exasol' then '"' || c."exa_column_name" || '"' else c."column_name_delimited" end || ')) as decimal(36,0))'
end
when "metric_id" = 4 then 'cast(count(distinct(' || case when "db_system" = 'Exasol' then '"' || c."exa_column_name" || '"' else c."column_name_delimited" || ' (casespecific)' end || ')) as decimal(36,0))'
end
when c."data_type" in ( 'YR', --interval year
'YM', --interval year to month
'MO', --interval month
'DY', --interval day
'DH', --interval day to hour
'DM', --interval day to minute
'DS', --interval day to second
'HR', --interval hour
'HM', --interval hour to minute
'HS', --interval hour to second
'MI', --interval minute
'MS', --interval minute to second
'SC' --interval second
) then
case when "metric_id" = 2 then 'cast(count(distinct(' || case when "db_system" = 'Exasol' then '"' || c."exa_column_name" || '"' else c."column_name_delimited" end || ')) as decimal(36,0))'
end
when "metric_id" = 1 then 'cast(''' || case when "db_system" = 'Teradata' then '''' end || 'data type "' || c."data_type" ||'" not checked' || case when "db_system" = 'Teradata' then '''' end || ''' as varchar(40))'
end "metric_column_expression",
case when c."ordinal_position" = 1 and "metric_id" = 0 then '"CNT"'
when "nullable" = 1 and "metric_id" = 1 then '"' || c."exa_column_name" || '_CNT_NUL"'
when c."data_type" in ( 'DA', --DATE
'AT', --TIME
'TZ', --TIME WITH TIME ZONE
'TS', --TIMESTAMP
'SZ', --TIMESTAMP WITH TIME ZONE
'I', --INTEGER
'I1', --BYTEINT
'I2', --SMALLINT
'I8', --BIGINT
'F', --DOUBLE PRECISION
'N', --NUMBER
'D' --DECIMAL
) then
case when "metric_id" = 2 then '"' || c."exa_column_name" || '_MIN"'
when "metric_id" = 3 then '"' || c."exa_column_name" || '_MAX"'
when "metric_id" = 4 then '"' || c."exa_column_name" || '_CNT_DST"'
when "metric_id" = 5 then '"' || c."exa_column_name" || '_AVG"'
end
when c."data_type" in ( 'PD', --PERIOD(DATE)
'PT', --PERIOD(TIME(n))
'PZ', --PERIOD(TIME(n) WITH TIME ZONE)
'PS', --PERIOD(TIMESTAMP(n))
'PM' --PERIOD(TIMESTAMP(n) WITH TIME ZONE)
) then
case when "metric_id" = 2 then '"' || c."exa_column_name" || '_BEGINNING_MIN"'
when "metric_id" = 3 then '"' || c."exa_column_name" || '_BEGINNING_MAX"'
when "metric_id" = 4 then '"' || c."exa_column_name" || '_END_MIN"'
when "metric_id" = 5 then '"' || c."exa_column_name" || '_END_MAX"'
when "metric_id" = 6 then '"' || c."exa_column_name" || '_CNT_DST"'
end
when c."data_type" in ( 'CF', --CHARACTER (fixed)
'CV' --CHARACTER (varying)
) then
case when not(c."data_type" = 'CF' and "character_maximum_length" > 2000) then
case when "metric_id" = 2 then '"' || c."exa_column_name" || '_MIN_LEN"'
when "metric_id" = 3 then '"' || c."exa_column_name" || '_MAX_LEN"'
end
when "metric_id" = 4 then '"' || c."exa_column_name" || '_CNT_DST"'
end
when c."data_type" in ( 'YR', --interval year
'YM', --interval year to month
'MO', --interval month
'DY', --interval day
'DH', --interval day to hour
'DM', --interval day to minute
'DS', --interval day to second
'HR', --interval hour
'HM', --interval hour to minute
'HS', --interval hour to second
'MI', --interval minute
'MS', --interval minute to second
'SC' --interval second
) then
case when "metric_id" = 2 then '"' || c."exa_column_name" || '_CNT_DST"'
end
when "metric_id" = 1 then 'not checked ''' || c."exa_column_name" || ''''
end "metric_column_name"
from vv_columns c
left join vv_primary_keys_raw p
on c."exa_table_schema" = p."exa_table_schema"
and c."exa_table_name" = p."exa_table_name"
and c."exa_column_name" = p."exa_column_name"
, (select 'Teradata' "db_system" union all select 'Exasol' "db_system")
, (select level -1 "metric_id" from dual connect by level <= 7)
where local."metric_column_expression" is not null
and 1 = ]] .. check_control .. [[
order by c."exa_table_name", c."ordinal_position" asc nulls first, "metric_id"
)
, vv_checks as (
select 'create or replace table "' || "exa_table_schema" || '"."' || "metric_table" || '" as ' ||
listagg("check_sql", ' union all ' ) within group(order by case when "db_system" = 'Exasol' then 1 else 2 end) || ';' as sql_text
from (
select "db_system", "exa_table_schema", "exa_table_name", "metric_table",
case when "db_system" = 'Teradata' then 'select * from (import from jdbc at ]] .. CONNECTION_NAME .. [[ statement ''' end ||
'select cast(''' || case when "db_system" = 'Teradata' then '''' end || "db_system" || case when "db_system" = 'Teradata' then '''' end || ''' as varchar(20)) as "DB_SYSTEM", ' ||
listagg("metric_column_expression" || ' as ' || "metric_column_name", ', ') within group(order by "ordinal_position", "metric_id") ||
' from ' ||
case when "db_system" = 'Exasol' then '"' || "exa_table_schema" || '"."' || "exa_table_name" || '"' else '"' || "table_schema" || '"."' || "table_name" || '"' end ||
case when "db_system" = 'Teradata' then ''') ' end
as "check_sql"
from vv_checks_expr
group by "db_system", "exa_table_schema", "exa_table_name", "table_schema", "table_name", "metric_table"
)
group by "exa_table_schema", "metric_table"
order by "exa_table_schema", "metric_table"
)
, vv_check_summary as (
select 1 ord2, 'create or replace table "' || "metric_schema" || '"."' || "exa_table_schema" || '_MIG_CHK" (schema_name varchar(128), table_name varchar(128), column_name varchar(128), metric_schema varchar(128), metric_table varchar(128), metric_name varchar(128), exasol_metric varchar(50), teradata_metric varchar(50), check_timestamp timestamp default current_timestamp);' as sql_text
from vv_checks_expr
group by "metric_schema", "exa_table_schema"
union all
select 2 ord2, 'insert into "' || "metric_schema" || '"."' || "exa_table_schema" || '_MIG_CHK" (schema_name, table_name, column_name, metric_schema, metric_table, metric_name, exasol_metric, teradata_metric) '
|| listagg(sql_text, '') within group(order by case when "db_system" = 'Exasol' then 1 else 2 end) || ' '
|| 'select e.schema_name, e.table_name, e.column_name, e.metric_schema, e.metric_table, e.metric_name, e.exasol_metric, t.teradata_metric from exasol e join teradata t on e.schema_name = t.schema_name and e.table_name = t.table_name and e.metric_name = t.metric_name; ' as sql_text
from (
select "db_system", "exa_table_schema", "exa_table_name", "metric_schema",
case when "db_system" = 'Exasol' then 'with ' else ', ' end || "db_system" || ' as ( '
|| listagg(
'select ''' || "exa_table_schema" || ''' as schema_name, ''' || "exa_table_name" || ''' as table_name, ''' || "exa_column_name" || ''' column_name, ''' || "metric_schema" || ''' metric_schema, ''' || "metric_table" || ''' metric_table, ''' || "metric_column_name" || ''' as metric_name, to_char(' || "metric_column_name" || ') as ' || "db_system" || '_metric from "' || "exa_table_schema" || '"."' || "metric_table" || '" where DB_SYSTEM = ''' || "db_system" || '''', ' union all ')
|| ' )' as sql_text
from vv_checks_expr
group by "db_system", "exa_table_schema", "exa_table_name", "metric_schema", "metric_table"
order by case when "db_system" = 'Exasol' then 1 else 2 end
)
group by "exa_table_schema", "exa_table_name", "metric_schema"
union all
select 3 ord2, '--select * from "' || "metric_schema" || '"."' || "exa_table_schema" || '_MIG_CHK" where exasol_metric != teradata_metric;' as sql_text
from vv_checks_expr
group by "metric_schema", "exa_table_schema"
)
select sql_text from (
select 1 ord, 1 ord2, sql_text from vv_create_schemas
UNION ALL
select 2 ord, 1 ord2, sql_text from vv_create_tables
UNION ALL
select 3 ord, 1 ord2, sql_text from vv_imports
UNION ALL
select 4 ord, 1 ord2, sql_text from vv_checks
UNION ALL
select 5 ord, ord2, sql_text from vv_check_summary
UNION ALL
select 6 ord, 1 ord2, sql_text from vv_primary_keys
UNION ALL
select 7 ord, 1 ord2, sql_text from vv_foreign_keys
)
order by ord, ord2
]],{})
--output(res.statement_text)
return(res)
/
;
-- !!! Important: Please upload the Teradata JDBC-Driver via EXAOperation (Webinterface) !!!
-- !!! you can find an example here: https://docs.exasol.com/db/latest/loading_data/connect_sources/teradata.htm !!!
-- Create a connection to the Teradata database
create or replace connection teradata_db to 'jdbc:teradata://192.168.56.103/CHARSET=UTF8' user 'dbc' identified by 'dbc';
-- Depending on your Teradata installation, CHARSET=UTF16 instead of CHARSET=UTF8 could be the better choice - otherwise you get errors like this one:
-- [42636] ETL-3003: [Column=5 Row=0] [String data right truncation. String length exceeds limit of 2 characters] (Session: 1611884537138472475)
-- In that case, configure your connection like this:
-- create connection teradata_db to 'jdbc:teradata://some.teradata.host.internal/CHARSET=UTF16' user 'db_username' identified by 'exasolRocks!';
IMPORT FROM JDBC AT teradata_db
STATEMENT 'SELECT ''connection to teradata works''';
-- Finally start the import process
execute script database_migration.TERADATA_TO_EXASOL(
'TERADATA_DB' -- name of your database connection
,true -- case sensitivity handling for identifiers -> false: handle them case sensitiv / true: handle them case insensitiv --> recommended: true
,'%' -- schema filter --> '%' to load all schemas (except system schemas). Examples: 'CORE' (to migrate the 'CORE' schema), 'MART_%' (to migrate all schemas whose name starts with 'MART_')
,'%' -- table filter --> '%' to load all tables in the schemas considered. Examples: 'H_EMPLOYEE' (to migrate all the tables whose name is 'H_EMPLOYEE'), 'H_%' (to migrate all tables whose name starts with 'H_')
,false -- boolean flag to create checking tables. TRUE -> create/load checking tables / FALSE -> do not create/load checking tables. -> default = FALSE.
-- When the option is used, a checking table will be created and loaded for each individual table being migrated.
-- The checking table will be created in the same schema with the same name adding '_MIG_CHK' as a suffix.
-- A summary table for all the checking tables of a specific schema will be created in the database migration schema with the name of the migrated schema adding '_MIG_CHK' as a suffix.
)
--with output
;