Impact of inserting a DB2 column to an existing table. View previous topic :: :: View next topic. Hi, For one of our projects, we are planning to introduce a new column in an existing DB2 table. I would like to know if we really need to recompile all the cobol programs which uses the DB2 table or not. What will be the impact if we do not recompile the cobol programs which uses the DB2 Table.
Back to top. Yes, you need to recompile all cobol programs. If you do not recompile them, it will not select values while generating output.
I get the impression that gopalkulkarni didn't understand your question. I wouldn't place much value on the response. I'm sure the manuals hold your answers. Only need to compile program which is using this field. If you have increased file length, this will have junk values. You have to recompile the program which are interacting with this new column.
Though it could be used by the pre-compiler, the pre-compiler does not access the db2 catalogued tables, were everything that counts is stored. It depends also on how the new column is defined. Does it have a default value? Can it be NULL? Will it be indexed? If the program don't provide one, DB2 will act as defined and succeed or fail. If it fails, you will need to modify the definition or the program which implies a BIND.
Manage your Cookies Settings. Join Now login. Ask Question. I'd like to add a new column to an existing table at a specific column location I can drop the table and recreate it, but I would like to know whether it can be done in any other way.
Thanks for your help. A Carter.
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Sep 5 ' Post Reply. Share this Question. Serge Rielau. It's instantanious and online Knut Stolze. A table is comprised of a set of columns. Therefore, the column order is completely irrelevant conceptually. You can choose any order of the columns in your query. Thanks for replies. Here is the situation But, when I add a new column to a table, it is added after the last column Thanks A Carter.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Learn more. Asked 10 years, 6 months ago. Active 9 years, 10 months ago. Viewed 16k times. Active Oldest Votes. IBM i 7. David G David G 3, 19 19 silver badges 25 25 bronze badges. Recreate the table, with its original name, with the columns in the order that you want. When you're sure the data is intact, you can drop the renamed version of the table.
Michael Sharek Michael Sharek 4, 2 2 gold badges 26 26 silver badges 32 32 bronze badges. I have a feeling you are right but I am just hoping someone knows a super secret easy and safe way to do this Sign up or log in Sign up using Google.
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The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I need to add a new column ID of Type integer not null auto increment, and make it the primary key.
How can I do that without deleting the table? You need to have multiple steps because the identity values need to be added manually. Create a new table with the primary key field. Insert the records from the old table. Drop the old table and if you can, rename the new one. If you can't rename it, recreate it and populate from the one that now has the records.
Building on Chamila Wijayarathna's answerI used the following:. Learn more. DB2 add auto increment column to an existing table Ask Question.
Oracle ALTER TABLE ADD Column By Examples
Asked 4 years, 2 months ago. Active 3 months ago. Viewed 12k times. I have a table with following schema in my DB2 database. Chamila Wijayarathna Chamila Wijayarathna 1, 3 3 gold badges 24 24 silver badges 39 39 bronze badges.
Has the table already values? What did you try so far, any errors, anything learned to share? Active Oldest Votes. I could do this successfully using following set of queries. There is an easy way to do it. Tested and working on DB2 for i V7R2. Mita Mita 1 1 silver badge 5 5 bronze badges. This isn't working for me on DB2 Dan Bracuk Dan Bracuk I want to do it without deleting the existing table.
Ramazan Polat Ramazan Polat 3, 1 1 gold badge 32 32 silver badges 48 48 bronze badges.
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Featured on Meta. Feedback on Q2 Community Roadmap. Technical site integration observational experiment live on Stack Overflow.Also, the new column might become the rightmost column of the table, depending on whether you use basic row format or reordered row format. The physical records are not actually changed until values are inserted in the new column. However, to use the new column in a program, you need to modify and recompile the program and bind the plan or package again. Access time to the table is not affected immediately, unless the record was previously fixed length.
If the record was fixed length, the addition of a new column causes Db2 to treat the record as variable length, and access time is affected immediately. When you retrieve an existing row from the table, a default value is provided for the new column. Except in the following cases, the value for retrieval is the same as the value for insert:.
If the new column is a short string column, you can specify a field procedure for it. The following example adds a column to the table DSN DEPT, which contains a location code for the department.
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The reason is that it would change the physical structure of the table, i. This would be quite expensive. It requires a significant amount of space and time. Learn more. DB2: How to add new column between existing columns? Ask Question. Asked 3 years, 1 month ago. Active 2 years, 8 months ago. Viewed 8k times. Mohit Mohit 99 1 1 gold badge 3 3 silver badges 12 12 bronze badges.
I don't think DB2 supports this syntax. You basically need to create another table. Active Oldest Votes. Drop table and indexes Create table with the new colunn Load data with old values Recreate all indexes and runstats. Once you have done it a few times it becomes old hat. Hogan Hogan Mohit I love it!
Accepted answer with Esperento57 Esperento57 Thank you, it was not that it was proposed and that I answered. Sign up or log in Sign up using Google. Sign up using Facebook.This statement can be embedded in an application program or issued interactively.
To alter a system-period temporal table when one or more of the changes also result in changes to the associated history table, the privileges that are held by the authorization ID of the statement must also include at least one of the following:. If the database is implicitly created, the database privileges must be on the implicit database or on DSNDB The value of n cannot be greater than For a dependent table, n cannot be greater than The column cannot be added if the increase in the total byte count of the columns exceeds the maximum row size.
The maximum row size for the table is eight less than the maximum record size as described in Maximum record size. For details about adding a LOB column, such as the other objects that might be implicitly created or need to be explicitly created, see Creating a table with LOB columns.
The implicitly created objects are owned by the owner of the base table. These privileges are required for implicitly created XML objects. The table must not be a history table or archive table. If the table is a system-period temporal table, the column is also added to the associated history table.
If the table is an archive-enabled table, the column is also added to the associated archive table. The following attributes of the column in the associated table are the same as the attributes of the corresponding column of the table that is being altered:.
If the column that is being added is a security label column, row permissions, including the default row permission, cannot exist for the table. If the column is to be used in the definition of the foreign key of a referential constraint, the data type of the corresponding column of the parent key must have the same distinct type. Db2 provides the default for a security label column. Use of this clause or keyword might invalidate packages that depend on the target object, or packages that depend on related objects through cascading effects.
See Changes that invalidate packages. If the column is defined as timestamp with time zone, the default value must include a time zone.
Adding a column to an index when you add the column to a table
A default value other than the one that is listed above can be specified in one of the following forms:. A character or string constant must be short enough so that its UTF-8 representation requires no more than bytes.
A hexadecimal graphic string GX constant cannot be specified. If a user-supplied value is specified for a ROWID column, Db2 uses the value only if both of the following conditions are true:. The name of this index is 'I' followed by the first ten characters of the column name followed by seven randomly generated characters. If the column name is less than ten characters, Db2 adds underscore characters to the end of the name until it has ten characters.
For an identity column, Db2 inserts a specified value but does not verify that it is a unique value for the column unless the identity column has a unique, single-column index. If a user-supplied value is specified for an identity column, Db2 inserts the specified value but does not perform any special validation on that value beyond the normal validation that is performed for any column. Db2 does not check how the specified value affects the sequential properties that are defined for the identity column.
To ensure uniqueness of the values, define a unique, single-column index on the identity column. This value is not necessarily the value that would be cycled to after reaching the maximum or minimum value for the identity column. If the value is positive or zero, the sequence of values for the identity column ascends. If the value is negative, the sequence of values descends.
However, if a unique index exists on the identity column and a non-unique value is generated for it, an error occurs. During a system failure, all cached identity column values that are yet to be assigned might be lost and will not be used.