Leon Mika
a1717572c5
Augmented expressions so that queries that can be executed as queries on DynamoDB can be done so. Also added an IR tree which is a simplified representation of the AST and will be used to plan the query.
82 lines
2 KiB
Go
82 lines
2 KiB
Go
package queryexpr
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import (
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"github.com/aws/aws-sdk-go-v2/feature/dynamodb/expression"
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"github.com/lmika/audax/internal/dynamo-browse/models"
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"github.com/pkg/errors"
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)
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func (a *astBinOp) evalToIR(info *models.TableInfo) (irAtom, error) {
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v, err := a.Value.goValue()
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if err != nil {
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return nil, err
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}
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switch a.Op {
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case "=":
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return irFieldEq{name: a.Name, value: v}, nil
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case "^=":
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strValue, isStrValue := v.(string)
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if !isStrValue {
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return nil, errors.New("operand '^=' must be string")
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}
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return irFieldBeginsWith{name: a.Name, prefix: strValue}, nil
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}
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return nil, errors.Errorf("unrecognised operator: %v", a.Op)
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}
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func (a *astBinOp) String() string {
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return a.Name + a.Op + a.Value.String()
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}
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type irFieldEq struct {
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name string
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value any
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}
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func (a irFieldEq) canBeExecutedAsQuery(info *models.TableInfo, qci *queryCalcInfo) bool {
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if a.name == info.Keys.PartitionKey || a.name == info.Keys.SortKey {
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return qci.addKey(info, a.name)
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}
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return false
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}
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func (a irFieldEq) calcQueryForScan(info *models.TableInfo) (expression.ConditionBuilder, error) {
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return expression.Name(a.name).Equal(expression.Value(a.value)), nil
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}
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func (a irFieldEq) calcQueryForQuery(info *models.TableInfo) (expression.KeyConditionBuilder, error) {
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return expression.Key(a.name).Equal(expression.Value(a.value)), nil
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}
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func (a irFieldEq) operandFieldName() string {
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return a.name
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}
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type irFieldBeginsWith struct {
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name string
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prefix string
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}
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func (a irFieldBeginsWith) canBeExecutedAsQuery(info *models.TableInfo, qci *queryCalcInfo) bool {
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if a.name == info.Keys.SortKey {
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return qci.addKey(info, a.name)
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}
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return false
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}
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func (a irFieldBeginsWith) calcQueryForScan(info *models.TableInfo) (expression.ConditionBuilder, error) {
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return expression.Name(a.name).BeginsWith(a.prefix), nil
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}
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func (a irFieldBeginsWith) calcQueryForQuery(info *models.TableInfo) (expression.KeyConditionBuilder, error) {
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return expression.Key(a.name).BeginsWith(a.prefix), nil
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}
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func (a irFieldBeginsWith) operandFieldName() string {
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return a.name
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}
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