本文使用的csv文件從這個鏈接裡下載：
http://grouplens.org/datasets/movielens/latest/
SAP HANA XS) enables you to create database schema, tables, views, and sequences as design-time files in the repository.
這個練習裡，我們將會使用SAP HANA Extended Application Services (XS）提供的database schema,tables和views來實現數據導入的效果。
The HDBtable syntax is a collective term which includes the different configuration schema for each of the various design-time data artifacts, for example: schema (.hdbschema), sequence (.hdbsequence), table (.hdbtable), and view (.hdbview).
This is why we will be using the SAP HANA HDBtable syntax including Core Data Service (CDS) artifacts instead, which only requires the SAP HANA Web-based Development Workbench available with any SAP HANA MDC on the SAP Cloud Platform. All the objects will be created as design-time and will allow us to adapt the structure easily without reloading the data.
首先在SAP Cloud Platform Neo環境的HANA MDC實例裡，打開HANA Web-based development workbench，切換到Catalog視圖：
點擊SQL，使用SQL語句創建一個新的user： MOVIELENS_USER
DROP USER MOVIELENS_USER CASCADE;
CREATE USER MOVIELENS_USER PASSWORD Welcome18Welcome18 NO FORCE_FIRST_PASSWORD_CHANGE;
ALTER USER MOVIELENS_USER DISABLE PASSWORD LIFETIME;
call _SYS_REPO.GRANT_ACTIVATED_ROLE ('sap.hana.ide.roles::CatalogDeveloper' ,'MOVIELENS_USER');
call _SYS_REPO.GRANT_ACTIVATED_ROLE ('sap.hana.ide.roles::Developer' ,'MOVIELENS_USER');
call _SYS_REPO.GRANT_ACTIVATED_ROLE ('sap.hana.ide.roles::EditorDeveloper' ,'MOVIELENS_USER');
call _SYS_REPO.GRANT_ACTIVATED_ROLE ('sap.hana.xs.ide.roles::CatalogDeveloper' ,'MOVIELENS_USER');
call _SYS_REPO.GRANT_ACTIVATED_ROLE ('sap.hana.xs.ide.roles::Developer' ,'MOVIELENS_USER');
call _SYS_REPO.GRANT_ACTIVATED_ROLE ('sap.hana.xs.ide.roles::EditorDeveloper' ,'MOVIELENS_USER');
GRANT EXECUTE on _SYS_REPO.GRANT_ACTIVATED_ROLE TO MOVIELENS_USER WITH GRANT OPTION;
GRANT EXECUTE on _SYS_REPO.GRANT_SCHEMA_PRIVILEGE_ON_ACTIVATED_CONTENT TO MOVIELENS_USER WITH GRANT OPTION;
GRANT EXECUTE on _SYS_REPO.GRANT_PRIVILEGE_ON_ACTIVATED_CONTENT TO MOVIELENS_USER WITH GRANT OPTION;
GRANT EXECUTE on _SYS_REPO.REVOKE_ACTIVATED_ROLE TO MOVIELENS_USER WITH GRANT OPTION;
GRANT EXECUTE on _SYS_REPO.REVOKE_SCHEMA_PRIVILEGE_ON_ACTIVATED_CONTENT TO MOVIELENS_USER WITH GRANT OPTION;
GRANT EXECUTE on _SYS_REPO.REVOKE_PRIVILEGE_ON_ACTIVATED_CONTENT TO MOVIELENS_USER WITH GRANT OPTION;
GRANT "CREATE SCHEMA" TO MOVIELENS_USER;
GRANT REPO.READ on "public" TO MOVIELENS_USER;
GRANT REPO.MAINTAIN_IMPORTED_PACKAGES on "public" TO MOVIELENS_USER;
GRANT REPO.MAINTAIN_NATIVE_PACKAGES on "public" TO MOVIELENS_USER;
GRANT REPO.EDIT_NATIVE_OBJECTS on "public" TO MOVIELENS_USER;
GRANT REPO.EDIT_IMPORTED_OBJECTS on "public" TO MOVIELENS_USER;
GRANT REPO.ACTIVATE_NATIVE_OBJECTS on "public" TO MOVIELENS_USER;
GRANT REPO.ACTIVATE_IMPORTED_OBJECTS on "public" TO MOVIELENS_USER;
執行後，該用戶創建成功：
註銷SYSTEM用戶，使用新創建的用戶登錄：
切換到Editor視圖：
在content節點下，右鍵菜單，新建一個Application：
Package維護成public.aa.movielens:
新建三個package，分別為data, hdb和service：
將之前鏈接裡提供的csv文件導入data package內：
HANA schema是存放HANA數據庫對象諸如表，視圖，存儲過程等的容器。
新建一個.hdbschema文件，內容如下：
schema_name="MOVIELENS":
再創建一個user.hdbrole文件：
內容如下：
role public.aa.movielens.hdb::user extends catalog role "sap.pa.apl.base.roles::APL_EXECUTE", "AFLPM_CREATOR_ERASER_EXECUTE", "AFL__SYS_AFL_AFLPAL_EXECUTE"
{
schema public.aa.movielens.hdb:MOVIELENS.hdbschema: SELECT, EXECUTE, CREATE ANY;
}
這個role定義了我們創建的這個應用工作時需要的權限：
最後創建CDS artifacts：
新建一個data.hdbdd文件：
namespace public.aa.movielens.hdb;
@Schema : 'MOVIELENS'
context "data" {
@Catalog.tableType : #COLUMN
Entity LINKS {
key MOVIEID : Integer;
IMDBID : Integer;
TMDBID : Integer;
};
@Catalog.tableType : #COLUMN
Entity MOVIES {
key MOVIEID : Integer;
TITLE : String(255);
GENRES : String(255);
};
@Catalog.tableType : #COLUMN
Entity RATINGS {
key USERID : Integer;
key MOVIEID : Integer;
RATING : hana.SMALLDECIMAL;
TIMESTAMP : Integer;
};
@Catalog.tableType : #COLUMN
Entity TAGS {
key USERID : Integer;
key MOVIEID : Integer;
key TAG : String(255);
TIMESTAMP : Integer;
};
};
使用下列的SQL語句將新創建的user role分配給用戶MOVIELENS_USER:
call _SYS_REPO.GRANT_ACTIVATED_ROLE ('public.aa.movielens.hdb::user','MOVIELENS_USER');
創建一個table-import配置文件，在裡面指定存儲於csv文件裡的數據，按照怎樣的邏輯寫入HANA MDC的持久化對象，比如數據庫表裡。
hdb package裡創建一個新的文件
data.hdbti ：import = [
{
table = "public.aa.movielens.hdb::data.LINKS";
schema = "MOVIELENS" ;
file = "public.aa.movielens.data:links.csv";
header = true;
delimField = ",";
delimEnclosing= "\"";
},
{
table = "public.aa.movielens.hdb::data.MOVIES";
schema = "MOVIELENS" ;
file = "public.aa.movielens.data:movies.csv";
header = true;
delimField = ",";
delimEnclosing = "\"";
},
{
table = "public.aa.movielens.hdb::data.RATINGS";
schema = "MOVIELENS" ;
file = "public.aa.movielens.data:ratings.csv";
header = true;
delimField = ",";
delimEnclosing= "\"";
},
{
table = "public.aa.movielens.hdb::data.TAGS";
schema = "MOVIELENS" ;
file = "public.aa.movielens.data:tags.csv";
header = true;
delimField = ",";
delimEnclosing= "\"";
}
];
此時執行下列SQL語句，就可以成功從HANA MDC實例的數據庫表裡讀取源自csv文件裡的數據了：
select 'links' as "table name", count(1) as "row count" from "MOVIELENS"."public.aa.movielens.hdb::data.LINKS"
union all
select 'movies' as "table name", count(1) as "row count" from "MOVIELENS"."public.aa.movielens.hdb::data.MOVIES"
union all
select 'ratings' as "table name", count(1) as "row count" from "MOVIELENS"."public.aa.movielens.hdb::data.RATINGS"
union all
select 'tags' as "table name", count(1) as "row count" from "MOVIELENS"."public.aa.movielens.hdb::data.TAGS";
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