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SQL programmingYou can use the HCL OneDB™ implementation of the SQL language to develop applications for HCL OneDB™ database servers.
Guide to SQL: SyntaxThe HCL OneDB™ Guide to SQL: Syntax describes the syntax of the statements, data types, expressions, operators, and built-in functions of the HCL OneDB™ dialect of the SQL language.
SQL statementsThis chapter describes the syntax and semantics of SQL statements that are recognized by HCL OneDB™.
REVOKE statementUse the REVOKE statement to cancel access privileges or roles that are held by users, by roles, or by PUBLIC, or to cancel user security labels or exemptions from the rules of security policies.
Table-Level Privileges
When to Use REVOKE Before GRANT
Restricting Access to Specific Columns

Restricting Access to Specific Columns

Unlike GRANT, the REVOKE statement has no syntax to specify privileges on a subset of columns in a table. To revoke the Select, Update, or References privilege on a column from a user, you must revoke the privilege for all the columns of the table. To provide access to some of the columns on which you previously had granted privileges, issue a new GRANT statement to restore the appropriate privilege on specific columns.

The next example cancels Select privileges for PUBLIC on certain columns:

REVOKE SELECT ON customer FROM PUBLIC;
GRANT SELECT (fname, lname, company, city) ON customer TO PUBLIC;

In the next example, mary first receives the ability to reference four columns in customer, then the table owner restricts references to two columns:

GRANT REFERENCES (fname, lname, company, city) ON customer TO mary;
REVOKE REFERENCES ON customer FROM mary;
GRANT REFERENCES (company, city) ON customer TO mary;