Prerequisites

Executing Custom DB Scripts

Custom scripts are executed to support input keywords that do not exist in certain versions of the target database. These scripts must be executed in each target database before the migration.

Table 1 describes the custom scripts in the DSC/scripts/ directory. For details about how to execute custom scripts, see Custom DB Script Configuration.

**Table 1** Custom DB scripts
Script	Description
date_functions.sql	Custom DB script for Oracle date functions
environment_functions.sql	Custom DB script for Oracle environment functions
string_functions.sql	Custom DB script for Oracle string functions.
pkg_variable_scripts.sql	Custom DB script for Oracle package variable functions
sequence_scripts.sql	Custom DB script for Oracle sequence functions
mig_fn_get_datatype_short_name.sql	Custom DB script for Teradata functions
mig_fn_castasint.sql	Custom DB script for migration of CAST AS INTEGER
vw_td_dbc_tables.sql	Custom DB script for migration of DBC.TABLES
vw_td_dbc_indices.sql	Custom DB script for migration of DBC.INDICES

**Table 2** Custom DB scripts (Oracle to GaussDB T)
Script	Description
create_user_and_temptable_enable.sql	Custom DB script for create user and local temporary table is used to address Oracle Package feature.
pkg_variable_scripts.sql	Custom DB script for Oracle package variable functions

Follow the steps to execute custom DB scripts:

Use any of the following methods to execute the required scripts in all target databases for which migration is to be performed:
- Use gsql.
  - Use gsql to connect to the target database and paste all content in the SQL file to gsql, which will automatically execute the pasted contents.
    Run the following command to connect to the database:
```
gsql -h <host_addr_xxx.xxx.xxx.xxx> -d <database_name> -U <user_name> -W <password> -p <port_number> -r
```
  - Use gsql to connect to the target database and execute a SQL file.
    Run the following command to connect to the database and run the SQL file:
```
gsql -h <host_addr_xxx.xxx.xxx.xxx> -d <database_name> -U <user_name>  -W <password>  -p <port_number> -f <filename.sql> -o <output_filename> -L <log_filename.log>  -r
```
- Use Data Studio.
  Use Data Studio to connect to the target database, and then open and run the SQL file in Data Studio.

Custom DB Script Configuration

Custom scripts are SQL files used to migrate from Teradata/Oracle the input keywords that do not exist in the target database.

These scripts must be executed in each target database before the migration.

Open the scripts folder in the release package. Table 3 lists the folders and files in the scripts folder.

The SQL files contain the scripts for the custom migration functions. These functions are required to support the specific features of Teradata and Oracle.

**Table 3** Custom DB scripts for DSC
Folder	Script File	Description
-- scripts	-	Folder: all scripts
------ oracle	-	Folder: Oracle functions and scripts
-------- sequence	-	Folder: scripts to configure Oracle sequences
-	sequence_scripts.sql	Script: used to enable migration of Oracle sequence
-------- package	-	Folder: scripts to configure Oracle package variables
-	pkg_variable_scripts.sql	Script: used to enable migration of Oracle package variables
-------- function	-	Folder: scripts to configure Oracle system functions
-	date_functions.sql	Script: used to enable migration of Oracle date functions
-	environment_functions.sql	Script: used to enable migration of Oracle environment functions
-	string_functions.sql	Script: used to enable migration of Oracle string functions
------ teradata	-	Folder: Teradata functions and scripts
-------- view	-	Folder: scripts to configure views
-	vw_td_dbc_tables.sql	Script: used to enable migration of Teradata DBC.TABLES
-	vw_td_dbc_indices.sql	Script: used to enable migration of Teradata DBC.INDICES
-------- function	-	Folder: scripts to configure Teradata system functions
-X	mig_fn_get_datatype_short_name.sql	Script: used to enable migration of Teradata DBC.COLUMNS
-	mig_fn_castasint.sql	Script: used to enable migration of CAST AS INTEGER
--------db_scripts	-	Folder: scripts to enable Teradata custom functions
-	mig_fn_get_datatype_short_name.sql	Script: used to enable migration of Teradata DBC.COLUMNS
--------core	-	Folder: Teradata core scripts
-	teradatacore.pm	Script: used to perform Perl migration

Configuring DSC and Migration Properties

To configure DSC, configure parameters in the configuration files in the config folder of DSC. Table 4 describes the parameters.

**Table 4** Parameters for configuring DSC
Scenario	Configuration File	Parameter
Teradata SQL Migration	DSC: application.properties Teradata SQL Configuration: features-teradata.properties	deleteToTruncate=True/False distributeByHash=one/many extendedGroupByClause=True/False inToExists=True/False rowstoreToColumnstore=True/False session_mode=Teradata/ANSI tdMigrateDollar=True/False tdMigrateALIAS=True/False tdMigrateNULLIFZero=True/False tdMigrateZEROIFNULL=True/False volatile=local temporary/unlogged
Oracle SQL Migration	DSC: application.properties Oracle SQL Configuration: features-oracle.properties	exceptionHandler=True/False TxHandler=True/False foreignKeyHandler=True/False globalTempTable=GLOBAL/LOCAL onCommitDeleteRows=Delete/Preserve maxValInSequence=0..9223372036854775807 mergeImplementation=WITH/SPLIT RemoveHashPartition=True/False RemoveHashSubPartition=True/False RemoveListPartition=True/False RemoveListSubPartition=True/False RemoveRangeSubPartition=True/False MigSupportSequence=True/False
Teradata Perl Migration	DSC: application.properties Teradata Perl Configuration: perl-migration.properties	add-timing-on=True/False db-bteq-tag-name=bteq db-tdsql-tag-name=sql_lang logging-level=error/warning/info migrate-variables=True/False remove-intermediate-files=True/False target_files=overwrite/cancel migrate-executequery=True/False
MySQL SQL Migration	DSC: application.properties MySQL SQL Configuration: features-mysql.properties	table.databaseAsSchema=true table.defaultSchema=public table.schema= table.orientation=ROW table.type=HASH table.partition-key.choose.strategy=com.huawei.hwclouds.scs.dws.DWSPartitionKeyChooserStrategy table.partition-key.name= table.compress.mode=NOCOMPRESS table.compress.level=0 table.compress.row=NO table.compress.column=LOW table.database.template=template0
Netezza SQL Migration	DSC: application.properties Netezza Configuration: features-netezza.properties	rowstoreToColumnstore=false
DB2 Syntax Migration	DSC: application.properties	exceptionHandler=True/False TxHandler=True/False foreignKeyHandler=True/False globalTempTable=GLOBAL/LOCAL onCommitDeleteRows=Delete/Preserve maxValInSequence=0..9223372036854775807 mergeImplementation=WITH/SPLIT RemoveHashPartition=True/False RemoveHashSubPartition=True/False RemoveListPartition=True/False RemoveListSubPartition=True/False RemoveRangeSubPartition=True/False MigSupportSequence=True/False