Out of interest, why do you want to update the primary key column and keep it as a continious number series? If does not needs to be. Updating the primary key column may defeat the idea the relational database when it comes to many table connected to your table. Figure 8.14 The Columns Tab. If you wish to create a composite primary key you can select multiple columns and check the PK check box. However, there is an additional step that is required, you must click the Indexes tab, then in the Index Columns panel you must set the desired order of the primary keys. Note that MySQL Workbench will.
-->You can define a primary key in SQL Server by using SQL Server Management Studio or Transact-SQL. Creating a primary key automatically creates a corresponding unique clustered index, or a nonclustered index if specified as such.
Before You Begin
Limitations and Restrictions
- A table can contain only one PRIMARY KEY constraint.
- All columns defined within a PRIMARY KEY constraint must be defined as NOT NULL. If nullability is not specified, all columns participating in a PRIMARY KEY constraint have their nullability set to NOT NULL.
Security
Permissions
Creating a new table with a primary key requires CREATE TABLE permission in the database and ALTER permission on the schema in which the table is being created.
Creating a primary key in an existing table requires ALTER permission on the table.
Using SQL Server Management Studio
To create a primary key
![Key Key](/uploads/1/3/3/2/133275730/945629407.png)
- In Object Explorer, right-click the table to which you want to add a unique constraint, and click Design.
- In Table Designer, click the row selector for the database column you want to define as the primary key. If you want to select multiple columns, hold down the CTRL key while you click the row selectors for the other columns.
- Right-click the row selector for the column and select Set Primary Key.
Caution
If you want to redefine the primary key, any relationships to the existing primary key must be deleted before the new primary key can be created. A message will warn you that existing relationships will be automatically deleted as part of this process.
A primary key column is identified by a primary key symbol in its row selector.
If a primary key consists of more than one column, duplicate values are allowed in one column, but each combination of values from all the columns in the primary key must be unique.
If you define a compound key, the order of columns in the primary key matches the order of columns as shown in the table. However, you can change the order of columns after the primary key is created. For more information, see Modify Primary Keys.
Using Transact-SQL
To create a primary key in an existing table
The following example creates a primary key on the column
TransactionID
in the AdventureWorks database.To create a primary key in a new table
The following example creates a table and defines a primary key on the column
TransactionID
in the AdventureWorks database.To create a primary key with clustered index in a new table
The following example creates a table and defines a primary key on the column
CustomerID
and a clustered index on TransactionID
in the AdventureWorks database.See Also
Use the Columns subtab to display and edit all the column information for a table. With this subtab, you can add, drop, and alter columns.
You can also use the Columns subtab to change column properties such as name, data type, and default value. The following figure shows an example of the Columns subtab.
Figure 8.14 The Columns Tab
Right-click a row under the
Column Name
column to open a pop-up menu with the following items: - Move Up: Move the selected column up.
- Move Down: Move the selected column down.
- Copy: Copies the column for a model.
- Cut: Copies and then deletes the column for a model.
- Paste: Pastes the column. If a column with the same name already exists, then
_copy1
is appended to the column name. - Delete Selected Columns: Select multiple contiguous columns by right-clicking and pressing the Shift key. Failed to generate rsa key pair on windows. Use the Control key to select separated columns.
- Refresh: Update all information in the Columns subtab.
- Clear Default: Clear the assigned default value.
- Default NULL: Set the column default value to
NULL
. - Default 0: Set the column default value to
0
. - Default CURRENT_TIMESTAMP: Available for
TIMESTAMP
data types. - Default CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP: Available for
TIMESTAMP
data types. https://conceptsclever852.weebly.com/blog/openssl-generate-key-pair-windows.
To add a column, click the
Column Name
field in an empty row and enter an appropriate value. Select a data type from the Datatype list. Select the column property check boxes as required according to the list of column properties that follow. For a description of each item, see CREATE TABLE. - PK: PRIMARY KEY
- NN: NOT NULL
- UQ: UNIQUE INDEX
- BIN: BINARY
- UN: UNSIGNED
- ZF: ZEROFILL Monster hunter generations key quests village.
- AI: AUTO_INCREMENT
- G: Generated ColumnThis option is available as of MySQL Server 5.7.
To change the name, data type, default value, or comment of a column, double-click the value to edit it.
Foreign Key
You can also add column comments to the
Column Comment
field. It is also possible to set the column collation, using the list in the Column Details panel. To the left of the column name is an icon that indicates whether the column is a member of the primary key. If the icon is a small key, that column belongs to the primary key, otherwise the icon is a blue diamond or a white diamond. A blue diamond indicates the column has NN set. To add or remove a column from the primary key, double-click the icon. You can also add a primary key by checking the
PRIMARY KEY
check box in the Column Details
section of the table editor. If you wish to create a composite primary key you can select multiple columns and check the PK check box. However, there is an additional step that is required, you must click the Indexes tab, then in the Index Columns panel you must set the desired order of the primary keys.
When entering default values, in the case of
CHAR
and VARCHAR
data types MySQL Workbench will attempt to automatically add quotation marks, if the user does not start their entry with one. For other data types the user must manage quoting if required, as it will not be handled automatically by MySQL Workbench. Pengertian Primary Key
Care must be taken when entering a default value for
ENUM
columns because a non-numeric default will not be automatically quoted. You must manually add single quote characters for the default value. Note that MySQL Workbench will not prevent you from entering the default value without the single quotation marks. If a non-numeric default value is entered without quotation marks, this will lead to errors. For example, if the model is reverse engineered, the script will contain unquoted default values for ENUM
columns and will fail if an attempt is made to run the script on MySQL Server. ENUM, BIT, and SET must contain at least one value when entering these data types into MySQL Workbench.