Pooled and Clustered Tables
The MANDT field of the table specifies whether the table is client independent or not.
Cluster tables and Pooled tables have many to one relationship with the underlying database.
A table pool corresponds to a table in the database in which all records from the pooled tables assigned to it are stored.
Several logical data records from different cluster tables can be stored together in one physical record in a table cluster.
A pooled table cannot have the name having more than 10 characters.
All the key fields of the pooled table must be of character data type.
In pooled tables, the maximum length of the key field/data fields should not exceed the length of varkey/vardata of the pool respectively.
In cluster table the records having the same key are stored in a single key in the cluster.
If there is an overflow of the data records a continuation record is created with the same table key.
The Table has a physical storage of data whereas views do not have physical storage of data.
The view is derived from one or more tables which is created only with the required fields from the database table(s). It can also be created with table inner joins and specifying conditions for data retrieval.
Projection view - Just retrieves some fields from a single table.
Help View - This is used for search help.
Database View - This is inner join view of one or more tables
Maintenance View - Helps in creating maintaining data of the application object. The data can be distributed among several tables.
No. You can use only projection view or database view in your ABAP program.
The Table Maintenance Generator is used to create table maintenance program to add, modify or delete records in the database table. This can be accessed using transaction SE54 or in SE11 using the menu Utilities->Table Maintenance Generator.
This specifies the screens to be created in the Table Maintenance Program.
Single step: Only overview screen is created i.e. the Table Maintenance Program will have only one screen where you can add, delete or edit records.
Two step: Two screens namely the overview screen and Single screen are created. The user can see the key fields in the first screen and can further go on to edit further details.
After making changes to the table, inorder to reflect the changes go to transaction SE14 and Choose Edit and then choose Activate and Adjust Database.
You can directly activate it from the SE11.
The programs are stored in the table TADIR and the development class packages in TDEVC.
You have to delete and recreate your own existing table maintenance program to see your new fields.
Whenever you need to create new records in the database table use INSERT. Whenever using INSERT be sure that a duplicate entry having the same values for the primary key fields are not present. Else it may throw a dump.
When you use MODIFY it makes a check for the matching key field values. If present it modifies the matching record, else it creates a new record in the database table.
Go to transaction SE11, open your database table. Choose the menu, Goto->Indexes to create index. Give your index name and choose the fields of the table. Be careful, an additional index may vanish with the next upgrade or hotpackage.
Check Table和Value Table的区别?
The Check Table is the dependent table to which the relationship is defined using foreign keys. The contents of the check table field are shown in the input help for the referenced field.
The Value table is the table attached to a field at the domain level, where the entry to the field can be only from the value table. They are not used in the Input Help.
The Domain specifies the Technical attributes of the field such as the data type, length and the value range.
The data element is an elementary type defining the description/text for the field when displaying on the screen and Parameter ID.
The reason for this is that the Domain for the field in the table might have Lowercase checkbox unchecked. Check the Lowercase checkbox to preserve the case of your data.
The reference table and reference field are the fields which specify the currency key or Unit of Measure. Suppose if the user specifies a currency amount say 1000$, the currency amount field would indicate the amount 1000 and the currency key indicates that the currency specified is in Dollars.
DD02L : SAP Tables
DD01T R/3 DD: domain texts
DD02ALL Table Parameters for ALLBASE
DD02DB2 DB2/390: Table Parameters
DD02DB6 DB6: Table Parameters for DB2 Version 2
DD02INF Table Parameters for INFORMIX, Version 6
DD02MSS Table Parameters for Microsoft SQL Server
DD02T SAP DD: SAP Table Texts
DD03L Table Fields
DD03T DD: Texts for fields (language dependent)
DD04L Data elements
DD04T R/3 DD: Data element texts
DD05S Foreign key fields
DD06L Pool/cluster structures
DD06T R/3 DD: texts on SQL tables
DD07L R/3 DD: values for the domains
DD07T DD: Texts for Domain Fixed Values (Languag
DD08L R/3 DD: relationship definitions
DD08T Texts on the relationship definitions
DD09C ABAP/4: Sytem-dependent attributes of tech
DD09L DD: Technical settings of tables
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