github.com/dolthub/go-mysql-server@v0.18.0/sql/plan/showdatabases.go (about)

     1  // Copyright 2020-2021 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package plan
    16  
    17  import (
    18  	"github.com/dolthub/go-mysql-server/sql"
    19  	"github.com/dolthub/go-mysql-server/sql/types"
    20  )
    21  
    22  // ShowDatabases is a node that shows the databases.
    23  type ShowDatabases struct {
    24  	Catalog sql.Catalog
    25  }
    26  
    27  var _ sql.Node = (*ShowDatabases)(nil)
    28  var _ sql.CollationCoercible = (*ShowDatabases)(nil)
    29  
    30  // NewShowDatabases creates a new show databases node.
    31  func NewShowDatabases() *ShowDatabases {
    32  	return new(ShowDatabases)
    33  }
    34  
    35  // Resolved implements the Resolvable interface.
    36  func (p *ShowDatabases) Resolved() bool {
    37  	return true
    38  }
    39  
    40  // Children implements the Node interface.
    41  func (*ShowDatabases) Children() []sql.Node {
    42  	return nil
    43  }
    44  
    45  func (*ShowDatabases) IsReadOnly() bool {
    46  	return true
    47  }
    48  
    49  // Schema implements the Node interface.
    50  func (*ShowDatabases) Schema() sql.Schema {
    51  	return sql.Schema{{
    52  		Name:     "Database",
    53  		Type:     types.LongText,
    54  		Nullable: false,
    55  	}}
    56  }
    57  
    58  // WithChildren implements the Node interface.
    59  func (p *ShowDatabases) WithChildren(children ...sql.Node) (sql.Node, error) {
    60  	if len(children) != 0 {
    61  		return nil, sql.ErrInvalidChildrenNumber.New(p, len(children), 0)
    62  	}
    63  
    64  	return p, nil
    65  }
    66  
    67  // CheckPrivileges implements the interface sql.Node.
    68  func (p *ShowDatabases) CheckPrivileges(ctx *sql.Context, opChecker sql.PrivilegedOperationChecker) bool {
    69  	//TODO: Having the "SHOW DATABASES" privilege should allow one to see all databases
    70  	// Currently, only shows databases that the user has access to
    71  	return true
    72  }
    73  
    74  // CollationCoercibility implements the interface sql.CollationCoercible.
    75  func (*ShowDatabases) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID, coercibility byte) {
    76  	return sql.Collation_binary, 7
    77  }
    78  
    79  func (p ShowDatabases) String() string {
    80  	return "ShowDatabases"
    81  }