102 lines
3.6 KiB
Go
102 lines
3.6 KiB
Go
package jet
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// Projection is interface for all projection types. Types that can be part of, for instance SELECT clause.
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type Projection interface {
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serializeForProjection(statement StatementType, out *SQLBuilder)
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serializeForJsonObjEntry(statement StatementType, out *SQLBuilder)
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serializeForRowToJsonProjection(statement StatementType, out *SQLBuilder)
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fromImpl(subQuery SelectTable) Projection
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}
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// SerializeForProjection is helper function for serializing projection outside of jet package
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func SerializeForProjection(projection Projection, statementType StatementType, out *SQLBuilder) {
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projection.serializeForProjection(statementType, out)
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}
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// ProjectionList is a redefined type, so that ProjectionList can be used as a Projection.
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type ProjectionList []Projection
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func (pl ProjectionList) fromImpl(subQuery SelectTable) Projection {
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newProjectionList := ProjectionList{}
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for _, projection := range pl {
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newProjectionList = append(newProjectionList, projection.fromImpl(subQuery))
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}
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return newProjectionList
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}
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func (pl ProjectionList) serializeForProjection(statement StatementType, out *SQLBuilder) {
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SerializeProjectionList(statement, pl, out)
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}
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func (pl ProjectionList) serializeForJsonObjEntry(statement StatementType, out *SQLBuilder) {
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SerializeProjectionListJsonObj(statement, pl, out)
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}
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// As will create new projection list where each column is wrapped with a new table alias.
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// tableAlias should be in the form 'name' or 'name.*', or it can be an empty string, which will remove existing table alias.
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// For instance: If projection list has a column 'Artist.Name', and tableAlias is 'Musician.*', returned projection list will
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// have a column wrapped in alias 'Musician.Name'. If tableAlias is empty string, it removes existing table alias ('Artist.Name' becomes 'Name').
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func (pl ProjectionList) As(tableAlias string) ProjectionList {
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newProjectionList := ProjectionList{}
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for _, projection := range pl {
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switch p := projection.(type) {
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case ProjectionList:
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newProjectionList = append(newProjectionList, p.As(tableAlias))
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case ColumnList:
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newProjectionList = append(newProjectionList, p.As(tableAlias))
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case ColumnExpression:
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newProjectionList = append(newProjectionList, newAlias(p, joinAlias(tableAlias, p.Name())))
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case *alias:
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newAlias := *p
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_, columnName := extractTableAndColumnName(newAlias.alias)
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newAlias.alias = joinAlias(tableAlias, columnName)
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newProjectionList = append(newProjectionList, &newAlias)
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}
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}
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return newProjectionList
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}
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// Except will create new projection list in which columns contained in excluded column names are removed
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func (pl ProjectionList) Except(toExclude ...Column) ProjectionList {
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excludedColumnList := UnwidColumnList(toExclude)
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excludedColumnNames := map[string]bool{}
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for _, excludedColumn := range excludedColumnList {
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excludedColumnNames[excludedColumn.Name()] = true
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}
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var ret ProjectionList
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for _, projection := range pl {
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switch p := projection.(type) {
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case ProjectionList:
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ret = append(ret, p.Except(toExclude...))
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case ColumnExpression:
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if excludedColumnNames[p.Name()] {
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continue
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}
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ret = append(ret, p)
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}
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}
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return ret
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}
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func (pl ProjectionList) serializeForRowToJsonProjection(statement StatementType, out *SQLBuilder) {
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out.WriteRowToJsonProjections(statement, pl)
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}
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// JsonObjProjectionList redefines []Projection so projections can be serialized as json object key/values
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type JsonObjProjectionList []Projection
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func (j JsonObjProjectionList) serialize(statement StatementType, out *SQLBuilder, options ...SerializeOption) {
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out.IncreaseIdent()
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out.NewLine()
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SerializeProjectionListJsonObj(statement, j, out)
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out.DecreaseIdent()
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out.NewLine()
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}
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