USE Statements

USE statements are used to set the current database or catalog.

Run a USE statement

USE statements can be executed with the executeSql() method of the TableEnvironment, or executed in SQL CLI. The executeSql() method returns ‘OK’ for a successful USE operation, otherwise will throw an exception.

The following examples show how to run a USE statement in TableEnvironment and in SQL CLI.

  1. StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
  2. StreamTableEnvironment tEnv = StreamTableEnvironment.create(env);
  4. // create a catalog
  5. tEnv.executeSql("CREATE CATALOG cat1 WITH (...)");
  6. tEnv.executeSql("SHOW CATALOGS").print();
  7. // +-----------------+
  8. // |    catalog name |
  9. // +-----------------+
  10. // | default_catalog |
  11. // | cat1            |
  12. // +-----------------+
  14. // change default catalog
  15. tEnv.executeSql("USE CATALOG cat1");
  17. tEnv.executeSql("SHOW DATABASES").print();
  18. // databases are empty
  19. // +---------------+
  20. // | database name |
  21. // +---------------+
  22. // +---------------+
  24. // create a database
  25. tEnv.executeSql("CREATE DATABASE db1 WITH (...)");
  26. tEnv.executeSql("SHOW DATABASES").print();
  27. // +---------------+
  28. // | database name |
  29. // +---------------+
  30. // |        db1    |
  31. // +---------------+
  33. // change default database
  34. tEnv.executeSql("USE db1");
  1. val env = StreamExecutionEnvironment.getExecutionEnvironment()
  2. val tEnv = StreamTableEnvironment.create(env)
  4. // create a catalog
  5. tEnv.executeSql("CREATE CATALOG cat1 WITH (...)")
  6. tEnv.executeSql("SHOW CATALOGS").print()
  7. // +-----------------+
  8. // |    catalog name |
  9. // +-----------------+
  10. // | default_catalog |
  11. // | cat1            |
  12. // +-----------------+
  14. // change default catalog
  15. tEnv.executeSql("USE CATALOG cat1")
  17. tEnv.executeSql("SHOW DATABASES").print()
  18. // databases are empty
  19. // +---------------+
  20. // | database name |
  21. // +---------------+
  22. // +---------------+
  24. // create a database
  25. tEnv.executeSql("CREATE DATABASE db1 WITH (...)")
  26. tEnv.executeSql("SHOW DATABASES").print()
  27. // +---------------+
  28. // | database name |
  29. // +---------------+
  30. // |        db1    |
  31. // +---------------+
  33. // change default database
  34. tEnv.executeSql("USE db1")
  1. settings = EnvironmentSettings.new_instance()...
  2. table_env = StreamTableEnvironment.create(env, settings)
  4. # create a catalog
  5. table_env.execute_sql("CREATE CATALOG cat1 WITH (...)")
  6. table_env.execute_sql("SHOW CATALOGS").print()
  7. # +-----------------+
  8. # |    catalog name |
  9. # +-----------------+
  10. # | default_catalog |
  11. # | cat1            |
  12. # +-----------------+
  14. # change default catalog
  15. table_env.execute_sql("USE CATALOG cat1")
  17. table_env.execute_sql("SHOW DATABASES").print()
  18. # databases are empty
  19. # +---------------+
  20. # | database name |
  21. # +---------------+
  22. # +---------------+
  24. # create a database
  25. table_env.execute_sql("CREATE DATABASE db1 WITH (...)")
  26. table_env.execute_sql("SHOW DATABASES").print()
  27. # +---------------+
  28. # | database name |
  29. # +---------------+
  30. # |           db1 |
  31. # +---------------+
  33. # change default database
  34. table_env.execute_sql("USE db1")
  1. Flink SQL> CREATE CATALOG cat1 WITH (...);
  2. [INFO] Catalog has been created.
  4. Flink SQL> SHOW CATALOGS;
  5. default_catalog
  6. cat1
  8. Flink SQL> USE CATALOG cat1;
  10. Flink SQL> SHOW DATABASES;
  12. Flink SQL> CREATE DATABASE db1 WITH (...);
  13. [INFO] Database has been created.
  15. Flink SQL> SHOW DATABASES;
  16. db1
  18. Flink SQL> USE db1;

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USE CATLOAG

  1. USE CATALOG catalog_name

Set the current catalog. All subsequent commands that do not explicitly specify a catalog will use this one. If the provided catalog does not exist, an exception is thrown. The default current catalog is default_catalog.

USE

  1. USE [catalog_name.]database_name

Set the current database. All subsequent commands that do not explicitly specify a database will use this one. If the provided database does not exist, an exception is thrown. The default current database is default_database.