Check if extended property description already exists before adding

Question

So, I have a script that adds extended properties, some describing a table, some describing a column. How can I check if the extended property exists before adding it so that the script does not throw an error?

Answer 1

This first script checks if the extended property describing the table exists:

IF NOT EXISTS (SELECT NULL FROM SYS.EXTENDED_PROPERTIES WHERE [major_id] = OBJECT_ID('Table_Name') AND [name] = N'MS_Description' AND [minor_id] = 0)
EXECUTE sp_addextendedproperty @name = N'MS_Description', @value = N'This table is responsible for holding information.', @level0type = N'SCHEMA', @level0name = N'dbo', @level1type = N'TABLE', @level1name = N'Table_Name';

This second script checks if the extended property describing the column exists:

IF NOT EXISTS (SELECT NULL FROM SYS.EXTENDED_PROPERTIES WHERE [major_id] = OBJECT_ID('Table_Name') AND [name] = N'MS_Description' AND [minor_id] = (SELECT [column_id] FROM SYS.COLUMNS WHERE [name] = 'Column_Name' AND [object_id] = OBJECT_ID('Table_Name')))
EXECUTE sp_addextendedproperty @name = N'MS_Description', @value = N'This column is responsible for holding information for table Table_Name.', @level0type = N'SCHEMA', @level0name = N'dbo', @level1type = N'TABLE', @level1name = N'Table_Name', @level2type = N'COLUMN', @level2name = N'Column_Name';

Answer 2

Here is another stored procedure approach, similar to Ruslan K.'s, but that doesn't involve try/catch or explicit transactions:

-- simplify syntax for maintaining data dictionary

IF OBJECT_ID ('dbo.usp_addorupdatedescription', 'P') IS NOT NULL
    DROP PROCEDURE dbo.usp_addorupdatedescription;
GO

CREATE PROCEDURE usp_addorupdatedescription
        @table nvarchar(128),  -- table name
        @column nvarchar(128), -- column name, NULL if description for table
        @descr sql_variant     -- description text
AS
    BEGIN
        SET NOCOUNT ON;

        IF @column IS NOT NULL
            IF NOT EXISTS (SELECT NULL FROM SYS.EXTENDED_PROPERTIES
            WHERE [major_id] = OBJECT_ID(@table) AND [name] = N'MS_Description'
                  AND [minor_id] = (SELECT [column_id]
                                    FROM SYS.COLUMNS WHERE [name] = @column AND [object_id] = OBJECT_ID(@table)))
                EXECUTE sp_addextendedproperty @name = N'MS_Description', @value = @descr,
                                               @level0type = N'SCHEMA', @level0name = N'dbo', @level1type = N'TABLE',
                                               @level1name = @table, @level2type = N'COLUMN', @level2name = @column;
            ELSE
                EXECUTE sp_updateextendedproperty @name = N'MS_Description',
                                                  @value = @descr, @level0type = N'SCHEMA', @level0name = N'dbo',
                                                  @level1type = N'TABLE', @level1name = @table,
                                                  @level2type = N'COLUMN', @level2name = @column;
        ELSE
            IF NOT EXISTS (SELECT NULL FROM SYS.EXTENDED_PROPERTIES
            WHERE [major_id] = OBJECT_ID(@table) AND [name] = N'MS_Description'
                  AND [minor_id] = 0)
                EXECUTE sp_addextendedproperty @name = N'MS_Description', @value = @descr,
                                               @level0type = N'SCHEMA', @level0name = N'dbo',
                                               @level1type = N'TABLE', @level1name = @table;
            ELSE
                EXECUTE sp_updateextendedproperty @name = N'MS_Description', @value = @descr,
                                                  @level0type = N'SCHEMA', @level0name = N'dbo',
                                                  @level1type = N'TABLE', @level1name = @table;
    END
GO

Answer 3

I wrote simple stored procedure to add or update extended property 'MS_Description':

IF OBJECT_ID ('dbo.usp_addorupdatedescription', 'P') IS NOT NULL
    DROP PROCEDURE dbo.usp_addorupdatedescription;
GO

CREATE PROCEDURE usp_addorupdatedescription
    @table nvarchar(128),  -- table name
    @column nvarchar(128), -- column name, NULL if description for table
    @descr sql_variant     -- description text
AS
BEGIN
    SET NOCOUNT ON;

    DECLARE @c nvarchar(128) = NULL;

    IF @column IS NOT NULL
        SET @c = N'COLUMN';

    BEGIN TRY
        EXECUTE sp_updateextendedproperty  N'MS_Description', @descr, N'SCHEMA', N'dbo', N'TABLE', @table, @c, @column;
    END TRY
    BEGIN CATCH
        EXECUTE sp_addextendedproperty N'MS_Description', @descr, N'SCHEMA', N'dbo', N'TABLE', @table, @c, @column;
    END CATCH;
END
GO

Answer 4

Maybe my answer did not directly connect to this question, but I would like to point out that MS_Description is actually case sensitive, even we add it with SQL. If we use MS_DESCRIPTION instead of MS_Description, it will not show up in the SMSS table design view.

In my case, I have to do something like this to removed the existing description and add a correct one.

IF EXISTS (
    SELECT NULL
    FROM SYS.EXTENDED_PROPERTIES
    WHERE [major_id] = OBJECT_ID('TableName')
        AND [name] = N'MS_DESCRIPTION'
        AND [minor_id] = (
            SELECT [column_id]
            FROM SYS.COLUMNS
            WHERE [name] = 'ColumnName'
                AND [object_id] = OBJECT_ID('Tablename')
            )
    )
    EXEC sys.sp_dropextendedproperty @name = N'MS_DESCRIPTION'
        ,@level0type = N'SCHEMA'
        ,@level0name = N'dbo'
        ,@level1type = N'TABLE'
        ,@level1name = N'TableName'
        ,@level2type = N'COLUMN'
        ,@level2name = N'ColumnName'
    GO

EXEC sys.sp_addextendedproperty @name = N'MS_Description'
,@value = N'Description detail'
,@level0type = N'SCHEMA'
,@level0name = N'dbo'
,@level1type = N'TABLE'
,@level1name = N'TableName'
,@level2type = N'COLUMN'
,@level2name = N'ColumnName'

GO

Answer 5

Please find my extension to Brian Westrich's answer above, but this version allows the update and addition of any extended property on a table and column and not just the MS_Description. Also, it allows you to use the the stored procedure to add and update extended properties in different databases so you only need one copy on a server.

CREATE PROCEDURE dbo.AddOrUpdateExtendedProperty
     @Database      NVARCHAR(128)   -- Database name
    ,@Schema        NVARCHAR(128)   -- Schema name
    ,@Table         NVARCHAR(128)   -- Table name
    ,@Column        NVARCHAR(128)   -- Column name, NULL if description for table
    ,@PropertyName  NVARCHAR(128)   -- Property name
    ,@PropertyValue SQL_VARIANT     -- Property value
AS
BEGIN
    SET NOCOUNT ON;

    DECLARE @NSQL NVARCHAR(MAX);

    DECLARE @Level2Type NVARCHAR(128) = NULL;

    DECLARE @Params NVARCHAR(MAX) = N'@Schema NVARCHAR(128), @Table NVARCHAR(128), @Column NVARCHAR(128), @PropertyName NVARCHAR(128), @PropertyValue SQL_VARIANT';

    IF @Column IS NOT NULL
    BEGIN
        SET @NSQL = 'USE ' + @Database + ';

            IF NOT EXISTS
            (
                SELECT NULL FROM sys.extended_properties
                 WHERE     major_id = OBJECT_ID(''' + @Schema + '.' + @Table + ''')
                       AND name = @PropertyName
                      AND minor_id = (SELECT column_id
                                        FROM sys.columns
                                       WHERE     name = @Column
                                             AND object_id = OBJECT_ID(''' + @Schema + '.' + @Table + ''')
                                     )
            )
            BEGIN
                EXECUTE sp_addextendedproperty
                     @name = @PropertyName
                    ,@value = @PropertyValue
                    ,@level0type = N''SCHEMA''
                    ,@level0name = @Schema
                    ,@level1type = N''TABLE''
                    ,@level1name = @Table
                    ,@level2type = N''COLUMN''
                    ,@level2name = @Column;
            END
            ELSE
            BEGIN
                EXECUTE sp_updateextendedproperty
                     @name = @PropertyName
                    ,@value = @PropertyValue
                    ,@level0type = N''SCHEMA''
                    ,@level0name = @Schema
                    ,@level1type = N''TABLE''
                    ,@level1name = @Table
                    ,@level2type = N''COLUMN''
                    ,@level2name = @Column;
            END
        ';

        EXECUTE sp_executesql
             @NSQL
            ,@Params
            ,@Schema
            ,@Table
            ,@Column
            ,@PropertyName
            ,@PropertyValue;
    END
    ELSE
    BEGIN
        SET @NSQL = 'USE ' + @Database + ';

            IF NOT EXISTS
            (
                SELECT NULL
                  FROM sys.extended_properties
                 WHERE     major_id = OBJECT_ID(''' + @Schema + '.' + @Table + ''')
                       AND name = @PropertyName
                       AND minor_id = 0
            )
            BEGIN
                EXECUTE sp_addextendedproperty
                     @name = @PropertyName
                    ,@value = @PropertyValue
                    ,@level0type = N''SCHEMA''
                    ,@level0name = @Schema
                    ,@level1type = N''TABLE''
                    ,@level1name = @Table;
            END
            ELSE
            BEGIN
                EXECUTE sp_updateextendedproperty
                     @name = @PropertyName
                    ,@value = @PropertyValue
                    ,@level0type = N''SCHEMA''
                    ,@level0name = @Schema
                    ,@level1type = N''TABLE''
                    ,@level1name = @Table;
            END
        ';

        EXECUTE sp_executesql
             @NSQL
            ,@Params
            ,@Schema
            ,@Table
            ,@Column
            ,@PropertyName
            ,@PropertyValue;
    END
END

Answer 6

To check any of extended property that available for the given table use as below.

IF EXISTS(SELECT 1 FROM sys.extended_properties WHERE [major_id] = OBJECT_ID('<schema>.<table_name>') AND [name] = N'MS_Description')

If your table has more than one extended property, give the column ID as minor_id.

IF EXISTS(SELECT 1 FROM sys.extended_properties WHERE [major_id] = OBJECT_ID('<schema>.<table_name>') AND [name] = N'MS_Description' AND minor_id = 3)

Query sys.extended_properties catalog view to get all the extended properties in your database.

For more details use http://msdn.microsoft.com/en-us/library/ms177541(v=sql.110).aspx

Answer 7

Building on ScubaSteve's answer, the following queries will allow you to check for an MS_Description property on a column or table within a specified schema by name. To check for a table simply replace the predicate c.name = '<column>' with c.name IS NULL or d.minor_id = 0

To enumerate the MS_Description properties by schema use -

SELECT a.name as [schema], b.name as [table], c.name as [column], d.name, d.value
FROM sys.schemas a
JOIN sys.tables b ON a.schema_id = b.schema_id
LEFT JOIN sys.columns c ON b.object_id = c.object_id
JOIN sys.extended_properties d ON d.major_id = b.object_id AND d.minor_id = ISNULL(c.column_id,0)
WHERE a.name = '<schema>' AND b.name = '<table>' AND c.name = '<column>' AND d.name = 'MS_Description'

To check if an MS_Description property does not exist before adding it surround your add statement with -

IF NOT EXISTS (SELECT 1 FROM sys.schemas a JOIN sys.tables b ON a.schema_id = b.schema_id LEFT JOIN sys.columns c ON b.object_id = c.object_id JOIN sys.extended_properties d ON d.major_id = b.object_id AND d.minor_id = ISNULL(c.column_id,0)
               WHERE a.name = '<schema>' AND b.name = '<table>' AND c.name = '<column>' AND d.name = 'MS_Description'
               )
BEGIN
    --EXEC sp_addextendedproperty statement goes here
END

The joins in these queries could probably be ordered better to eliminate the ISNULL function, but this should get what you're looking for.